Best bet for performance parts is needswings.com. rob has downpipes with cut outs, and other exhaust opinions. From my research and watching the forum headers were made but are rare and the gain is a moot point. Most exhaust mods are for a sound preference. Eurocharged.com is a good sight if you want a larger pulley 181 or 185 or a tune. You can remove the ECU and mail it to them or buy the tuning cable and have them reflash the ECU with the tuning cable.