Get an 03 ECU.

 

I only have 31k.

Would switching to an 02,03 ECU give any power gains? Better Gas mileage, or just lean it out a little bit.

 

I have 38k on MY01. It is a mod I plan to do over the winter. It leans the air fuel ratio and provides better low end power. There are many threads on it, just do a search.

 

as long as the bumper does not have an oily residue from blow-by, i wouldn't worry. You should see how my stock exhaust looked after a day of driving with a turbo... Try leaning out the mixture with a VAFC, if you want a little more power and less carbon build up!