Performace upgrades for an 01 a4 1.8t quattro?
 

I got it about a week ago and im thinking about hooking it up with some performance parts (possibly a chip?) and i wanted to get some opinions on the best ones. I'm not sure if its a good idea though because the car has about 165k miles on it but it runs great. Any suggestions?

The chips are pretty much all the same, so your best option is the nearest chip dealer.

Nothing wrong with doing mods to that car. Just make sure to do a compression test to see if the motor is in good shape.

I checked out the a4 newbie guide and GIAC was a recommended choice for a chip. But if i do get one do i need anything else besides a new diverter valve? Also i read that my gas mileage will stay steady or even increase but if i got all that extra power wouldn't it translate into less gas mileage?

you might get less mileage. but trust me its worth it. i just got my chip today. i got it done at GRD (www.grdperformance.com) those guys are awesome check out the site i recommend them.

instead of a chip..u can do the diode/mbc...u can crank out more boost than a $500 chip for alot cheaper..

Boost is only 1/3 of tuning to make power. Plus the diode removes the safetly that will keep the motor from blowing up if the MBC fails and allows the K03 to hit 30psi.

get 60+ hp by adding a new soft.

Part of the new HP is by fine tuning the fuel and timing maps to increase efficiency. This usually means you get more power on the same, or even less, fuel at part throttle where most of us spend time at most of the time. If you constantly go heavy throttle, sure, you'll see a decrease. BTW, the true advertised gains are usually on the top end @ WOT anyways.