I've been told that I can use a mini DisplayPort to DVI adapter with the Thunderbolt port then just a HDMI to DVI in the HDMI port, is that possible?
That's what I do with a 2010 mini (MDP instead of TB).
Yes, it works perfectly.
The tricky part comes if you want three monitors. For that, you need to be sure to buy the video-boosted Mini model that has discrete graphics, or use a (slow) USB video adapter for the third screen. But for two, any modern mini is fine out of the box.
Can I connect to Mac Mini Remotely from Mac book?
Yes. You can use OS X's built-in screen sharing. It's a VNC-based application that ships with OS X. You'll need to enable it on your systems in order to use it. Open System Preferences -> Sharing. And make sure 'Screen Sharing' is checked. I recommend the excellent ScreenSharingMenulet -- sits in your menu bar and lists any Bonjour-enabled screen sharing hosts in a drop down when you click on it for automatic discovery and easy connection to shared screens in your network.
Do I need to buy any other hardware for the remote connection or I can do thru Wi-FI available in both Mac MINI and Mac book?
No additional hardware or software is required. You don't even need ScreenSharingMenulet -- you can find and connect to shared screens via Finder if you like.
You do say something confusing your question though:
My aim to have a logical system with 12 GB (8GB with Mac MINI + 4 GB in laptop)for running Virtual Machines on both Mac MINI and Mac Book and be able talk to each other.
You cannot tie the machines together using screen sharing. They won't present themselves as one logical, virtual device to any virtualization software with shared memory or CPUs or any such thing. They will act as completely separate machines, but they can be accessed, graphically, from one another.
If you're trying to tie the machines together to act as a single, unified "super computer" you need to look at much more complicated technologies than anything OS X ships with. Beowulf for clustering and something better than ethernet for inter-machine communication will be necessary like a fiber channel connection (and that will require more hardware).
What about the performance compared to direct and remote connections as it is vital for Virtual Machine communication.
It is difficult to give an answer to this question as it all depends on what you're trying to do when it comes to communication between the machines. On the remote access side of things: over my local wireless network the performance is decent if you use adaptive mode on the screen sharing application but it can get glitchy if you disable adaptive quality scaling. If my macs are all on wires on Gbit ethernet then non-adaptive scaling is quite good. Processes running within VMs on my Macs have good sustained throughput to the Mac's built-in ethernet and wireless network interfaces. Inter-process communication between VMs running on separate Macs is going to be completely dependent on your network and your processes -- impossible to give an answer that'll cover all cases I'm afraid. If you get more specific with what you're trying to do I could possibly answer this more succinctly.
Best Answer
There's no hardware or software difference.
As with all other retailers, everyone is free to set their own price. The price can be based on all sorts of parameters, which makes it impossible to say exactly why retailer A is xx$ cheaper or more expensive than retailer B.
It could be for example that a retailer has lower costs. For example having an online presence versus a physical presence is typical less costly. Similarly could spending different amounts on customer service, warranty repairs/support, etc.
It could also be that a retailer that is also the maker of the product wants to be in the market at a relatively high price in order to ensure that other retailers find it worth while to sell their products.
It could also be that one retailer earns money from other sources than the specific product sale - and that makes it possible for them to lower their price. For example by gathering data about the customer, or simply by having the customer browsing their web site making it more likely that they will buy other products from the same retailer.