We're hooking up the Apex-I turbo timer to a 2007 STI Limited. We need to figure out which wire at the ECU is the O2 signal wire...? Any help on color? We also need to find the ECU ground wire as well!

EDIT: how is the turbo cooled anyway? Isn't it mostly from a water jacket...therefore not needing a turbo timer at all?

Yes, no need for a TT for subies. Except for the cool factor when unsuspecting people walk by it.

Turbo timer FAQ-
http://forums.nasioc.com/forums/showthread.php?s=&threadid=465156
No you don't need one.