I tend to remain sceptical of anyone making claims without valid and reliable data. With that said, some practices you list are of critical importance; others, I'm not sold on one bit. Please don't take this a slight against you, but rather as a criticism of your general claims (and lack of scientific data therein). Moreover, if you enacted all those changes at once, you'll never know which one made a real difference, and which one did absolutely nothing. Proper scientific methodology calls for the manipulation of one variable against a control (unless you want to run the more complex ANOVA).
Clean your MacBook Pro fans from within... it's simple, open the
bottom closure and blow the hell out of these fans
Absolutely. This is by far the most effective way to ensure your system continues to operate nominally over the years. It is sadly also the most neglected. Dust sticks to the blades (and most of the internals) creating a "sticky" residue and not only prevents the fan's blades from spinning at their optimum, but seriously restricts air flow. Computers generally accumulate far more dust than people expect. Regular cleanings are essential!
Download and install Fan Control and run your fans @ 2800-3000 RPM
This of courses comes at a sacrifice to noise (increasing it) and I'd like to see data on how much cooler the chips operate with such a small increase to RPM.
Ditch all browsers to Safari, I tried them all Firefox up to version 5
and 7 (Aurora), Chrome and Opera... nothing beats the CPU usage (less
of it) than Safari. Also flash youtube videos run with less resources
on Safari for some reason
Again, I'd like to see some data being this claim. These guys have conducted some very loose tests that support your assertion, and I'm inclined to agree that Safari, being so tightly integrated into OS X should net improvements over its competitors across the board, but a few CPU cycles here and there aren't going to amount to a drop (drastic or modest) in temperatures (these saw extremely small differences in performance).
Use your faster GPU on AC Power, and lower on Battery power (use
http://codykrieger.com/gfxCardStatus for source-based GPU switching)
GPUs put off heat, wether they're integrated or discrete. I can see a reduction in power, but a reduction in heat, again, I'm not sold. In the case of MBP, models that possess discrete video cards have dual fans (one for the CPU and one for the GPU). So using the discrete card may kick off additional heat, but it's also got a dedicated fan to push that heat away from the machine. Stressing the integrated chip will see the CPU spike in temperatures, which means that fan will be doing more work to handle the additional load. It may be the case that the fan on the CPU (together with the integrated GPU) may be sufficient in pulling away the excess heat, but at no doubt the cost of excessive noise (generated by 6,000 RPMs). I don't know if anyone has done testing, but from my own anecdotal experience with my old MBP1,1, the GPU fans rarely switched gears (unless playing intensive games and then the issue would be moot as you'd want to use the discrete video). It was always the CPUs fans that took the brunt of the work.
Replace your internal hard drive with an SSD
Not only will this greatly improve performance, but it can't hurt in reducing temperatures. The idle/active power consumption of an SSD is about 0.5W to 2w, respectively. The average power consumption of a traditional HDD is about double that (1W to 2.5W, respectively). I won't know what that transfers to in the temperatures department, but it certainly can't hurt.
Keep your monitor running @ 90% brightness and keep your keyboard lights off or low
I'd love to see data on this. LED backlighting is already quite efficient and distributing heat, but I'm not sure a reduction (at least that small) in power would have any effect. As for the keyboard lights, those are LEDs and as is with such small LED bulbs, they are incredibly power efficient and produce little to no heat as a result.
With all that said, I'd saying re-application of Arctic Silver 5 (or thermal compound of equal quality) and the cleaning of dust from the internals is the most effective (and proven) way to keep your system cool. I've never seen data to convince me that turning off some service, or placing your system on a pad with a couple of fans does anything (other than perhaps keep the case cooler to the touch) worth merit.
Your trip the Genius bar was too focused in my opinion. I suggest you make another appointment and lay out your case above, but this time, don't mention the memory tests, but that the problems showed up when you upgraded the RAM. Refer them to your old case number (tack this visit on as a follow-up).
Tell the Genius on hand that the problems still exist and that they need to do further testing. As it stands, your Mac is unusable. Additionally, tell them to make note that you have tried a fresh re-installation and it did nothing to help (don't mention that things ran fine for a day or too, stick to the current state of the system), which will rule out any software problems.
Ask them on what they suggest and follow it (no matter how annoying it may be). If it doesn't fix it, call them and do another follow-up. If they tested the RAM and it passes, then it might be the logicboard.
In any case, do not visit them with "the solution." Let them find it through there own testing. Clearly, the logs containing kernel panics and all the problems you list will support your case. Moreover, their internal testing tools are much more sophisticated than what you'll scrounge up on the net through 3rd party apps (they actually have in-house diagnostic utilities for these occasions).
I would highly recommend that you stop spending your time diagnosing the problem and let them do it for you. That's what they're there for.
If after everything is said and done, and they still can't pinpoint a problem, you will likely walk away with a new Mac. Just focus on the problems you are suffering from and leave the diagnostics to the Geniuses and technicians.
You may want to downgrade back to the 4 GB for now. And it's of note that replacing the RAM and the hard drive yourself do not void your warranty for that particular Mac model.
PS: You don't specify if you took your notebook to an Apple Store and spoke with a Genius or some Apple authorized repair centre. I would strongly encourage you to deal with Apple directly. They'll not only treat you better, but likely solve the problem with less headache. My advice is tailored to them; you are totally on your own should you choose a 3rd party repair shop. To galvanize the need to deal with Apple, let me put forth the following. I had a friend who purchased a Mac mini. There were strange problems during boot up where it would occasionally load the keyboard set-up assistant. The machine was also sluggish and exhibited other unusual anomalies in its day to day. We took it into an Apple Store and the Genius tried to reproduce the errors. He couldn't. He also expressly stated that minis never required repair or servicing. But with all that, he elected to replace the entire unit and gave my friend a new mini. Took it back to his place and it hummed, no more issues. I doubt he would have received the same treatment from a computer store authorized to service Macs. Deal with Apple direct; I cannot stress that enough.
Best Answer
I'll list some general things to check in the order I would isolate them.
A great place to find pictures of your model is the iFixit repair guide - I'll use the Early 2011 15" iFixit guide for some tips below:
Look over your bottom case very carefully - you should see wear marks or fine dust or scratches where it is hitting the insides. If the noise is coming from the bottom case contact - you should see physical evidence of wear. If not, then focus on the other parts (fans, hidden debris stuck under the battery, board or other parts near the keyboard side of things, etc...)
It's probably from the bottom case, so look at all potential contact points where the bottom case can rub. When putting the bottom case on again, remember where these inserts are so you can press them and hear a click for each before screwing the fasteners. When open, inspect the clips very well - a broken clip or not getting the insert into the snap is a big cause of the bottom case moving around when in use.
Similarly, pay attention to the clearance between the battery indicator, keyboard ribbon ZIF socket and trackpad connector cage as well as the clips under the left hand side of the mac. Even a battery screw could be too high and scraping the case. Once you have exhausted the easy things, you may even need to remove and re-seat the components on the left hand side of the mac to ensure nothing is stuck under the topcase and between the components.
Unless you are a very good tech and know what things cost should they break, it might be better to take it in for service - especially if you can show the tech how to reproduce the noise. There are so many components, any one of which could be harboring a loose screw or piece of debris that made it's way in the heat exhaust vents - it's hard to guess what exactly is making your mac squeak.