look for a tuning chip. Try wetterauer,
www.chiptuning.com, email and ask if they have software. Or upsolute.com or speedtuning.com
The chips provide real bang for the buck. Aftermarket exhaust systems and sport air filters do little or nothing, and are sometimes not even noticeably faster, just louder. I just chipped my jetta tdi and gained 25 rear wheel hp and 40lbs torque. Talk about noticeable!