My Opinions on perfromance, all stuff that I've personally tried

Turbo  performance Upgrades

The Mopar Performance Computer is a good uprgrade. I didn't have any problems. I enjoyed the increased boost level. You can also talk to FWD performance about an even more powerful computer!

MP computer

Exhaust -

The exhaust system mods seem to be the most effective. Bigger is better. No back pressure is good! the turbo provides enough!

Intake -

A K&N filter, They flow the incredibly well. Great results. I currently have one right on the compressor.. seems to be working well :)

A graigner style bleed setup is a good way of adding some power, watch your air fuel ratio once you surpass 15-16 psi of boost.

Boost Bleed Systems -

Unless your computer is programmed for the larger injectors, or you're going to use an adjustable fuel pressure regulator. Bigger injectors aren't all that great. Adding a few VW cold start injectors with a pressure switch is much more effective

Injectors-

Tires -

On tires, I'd go with whatever will fit your car, and if you want to hook good on the track get a set of slicks. right now the Om, has 205/50 ZR 15's from the BF goodrich Comp T/A series, DOT street legal slicks aren't really worth it. the treadware versus the traction isn';t all that great. If you're gonna race the car. Spend your money wisely and invest in a set of slicks

I have an aluminum FM one on my car. I like it quite a bit. probably picked up 10hp. some noticeable seat of the pants improvement, also gives longer accessory life. means your alternator will live longer.

Underdrive pulley

Opening up the 1pieces of 2 piece intake is kind of a waste of time and effort. It flows well enough as is. If you don't believe me, ask Gary D, his K-car runs 10's on an untouched piece!!

Intake porting