Colin has a fair point. I've seen so many 2.5 with problems that I will never go that route again but that depends in how much power you want Chris.
Ultimate will be a 2.35 build
Or the one that I will go for would be a forge 2.1 build. Greer's have one for sale which means it's ready to go and all the machining work has been done to the cdb.
Bolt your heads on and new turbo and fmic and your off.