Re: 2008 Wrx Sti
My thought is buy the cheapest base WRX you can. They'll have a lot more resale value than STI's simply because more people can buy them, and the tuning junkies will be happy that it's a factory turbo car.
The STI is good, but for what you're planning to use it for, the WRX would probably suffice.
But if you really care about getting the "STI" engine and DCCD, then by all means go for it.