I am currently driving a 2005 bmw 645ci. I love the look of the car as I have blacked out my tail lights and windows, along with adding black rims. However I now want to increase my performance. Lately I have been posting questions about mufflers and performance chips, however I just need answers on performance. My engine is very sophisticated and hard to work on but I need more performance. Don't tell me to sell it and by a 99 M3 and mod that, I need specific Mods and websites to find them. I have about 4000$ I can spend right now that Ive earned as im only 16 and the car was a present from my dad. Are there superchargers for the 6 series? should I add an exhaust system? At this point im new to modifying cars but would really like to learn, all help is greatly appreciated!