Uhm.. he should really fix that boost controller... 18+ pounds on the stock turbo probably isnt wise.
Depending on what turbo you get, you usually need to upgrade the injectors/fuelpump/intercooler. You can get away with the stock intercooler, but most people upgrade it. A pretty popular upgrade is the VF34, STI injectors, and Walbro fuel pump.
The srt-4 is a quick car from a roll. Its fast in a straight line...
I wouldnt be pissed about losing to one, especially if its not from a stop. Also, the 4th gear of the wrx is its weakest... but at that point you are already going about 90.
The point is... you will lose to an SRT-4 if you are going in a straight line from a roll after 90 miles per hour. I don't know how often that situation comes up with you and your friends, but it doesnt happen very often to me.