Im looking at putting a 02-06 STi intercooler on my MY00.
Im pretty sure you dont have to do that someone on rexnet has done it and said The clutch fluid container can be cut down, i cut 25mm off mine, it is around 10mm above the high mark, Stanley knife does the job easy. The cap is still tight -ish in the hole, i will make a small clip to swing over it to make sure it can't come off, even std rally cars have them fall off.
So yeah the link is here if you want more info on it
http://www.rexnet.com.au/forum/index...howtopic=21945