Be sure to factor lead time in if you order Cobb heads. Like six months leads time. I ordered my stage II heads (for my RS) in October, and spoke to them yesterday and was told another 45-60 days. But I knew that up front, so no big deal. But some guys call up, slap down a deposit on heads without asking questions, and a month later, no heads, and a whiny pissed off purchaser who wants to blame Cobb for it.
As for the flow on the heads, read this discussion:
http://forums.nasioc.com/forums/showthr ... genumber=1
This is the original thread that the sticky in the turbo section cut and pasted, in it's entirety.
As for needing to replace the cams on either of the EJ25 heads for a boosted application, I disagree that it is needed, and the CFM's don't matter that much either. As has been mentioned, those Cobb numbers are static. With a turbo on those EJ25 heads, and their flow, you can push a hck of a lot of air through them and make plenty of power. Marc Rameriz makes over 350hp with his EJ22 w/EJ25 DOHC heads, and with stock cams to boot.
But with the current availabilty of v7 STi heads (which are similar to the new USDM heads on XT's and STI's) and the falling price, why even consider EJ25 heads. I recently passed on a deal for STi v7 heads for $600!!! That is if you want to rev the puke out of the thing. These heads are ready for 8000rpms from the factory. The Ej25 heads should not go past 6800rpm or so without stiffer springs. But with stiffer springs, you could rev those up too.
The big question is do you just want to buy some heads and slap them on, or do you want to build some heads?
He said that the 2.5rs heads were the best flowing and that I could get a set for about $1,300. 
