Recently bought my first rex (new 2011) and new member to club WRX. I was reading a PDF about the warranty and it seams like anything you mod to boost performance can come back to bite you on the warranty. For most things, I'll probably just order SPT parts and have the dealership install them to avoid that but I do want to replace the BPV with the Perrin recirc BOV. I was wondering if I did that and just put the stock BPV back on when I take it in for maintenance or to have it repaired if they might notice that? Very noobish question and I am a noob so any input would be appreciated... THANKS!!