I hate to disagree with you KAX (particularly because I just got my personal 2.0RST running) but there is more to an intake manifold design than restriction. Plenum volume and runner length are VERY important to performance. It's commonly accepted that plenum volume near double displacement is best on a turbo car - the stock plenum is closer to HALF the displacement of a 2.5. The stock runner length is LONG, which helps the bottom end but hurts the top. The shorter runners of the Cossie are more appropriate to 4500rpm+.

It "should" be a nice gain everywhere...

Siegel