I live in colorado and i would recomend taking your car to http://autosportwerks.com/ in Broomfield they are great. you may remember the in the Euro tuner S4 shoot out i think they got first place. that is were i take my car to get it worked on

 

well in the plane i would lean the mixture ahahahhahah..eh...hmm...ill stop now.. [sm=imsorry.gif]

i wish i was in colorado..

 

I would like to spend no more than $500 if possible, but realize that I may need to spend more to get what I am looking for. I dont think I could go any higher than $1,000.

 

Turbo cars have an altitude sensor. The turbo will spin faster (within its limits) to achive the requested boost. Perhaps you have a boost leak.
Naturally aspirated engines? Well they are just SOL.