Crap why didnt he continue this thread. I also have a stage 2 07 WRX with the Cobb AP & Cobb catted TBE. It also makes a ticking noise. Not at all when revving and not in gear, but under acceleration in 1st & 2nd from take-off till about 3k rpm or so, and only with the windows down. I can hear it no matter how much I get on it, but it is more pronounced at WOT. It is irritating, sounds just like an exhaust leak. From what I have read it is probably just wastegate flutter. Sound right? Any other possible explanations? Car has 15k on it and just had its 15k service. Asked dealer about it and they "claimed" they could not hear it when they drove it, which is complete bs.
2007 WRX sedan
Cobb Stage 2-protuned by P&L