I have a 2001 bmw 325i. I was wondering what parts add performance to it.
The two previous answers are correct, but I can tell you some better stuff.
Visit the website bavauto.com and you’ll find anything you need, and a little more.
If you are looking for a little extra umph, (without breaking the bank buying Dinan stuff, which is overrated in my opinion), a catback exhaust (remus, scorpion, agency power…), new air intake (conforti, dinan, AFE, K&N), underdrive pulleys (rogue engineering), ignition coils (bavauto.com), and headers will give your car more power for longer in the RPM range, and give it a nice, aggressive sound. If you are looking for big power though, forced induction is the way to go, but maintainence will go way up. From all the things I mentioned previously, you could expect to reasonably see these gains at the wheels: Cat back- 5-10 HP, Intake- 3-6 HP, Pulleys- 8-10 HP, Ignition- 1-2 HP, Headers- 5-10 Hp. Those may not be overwhelming numbers, but when combined your car will feel sharper, sound nice, and have a wider power band which is even better for everday use.
For all around performance, some drilled and slotted rotors not only look nice, but they also improve braking, as do stainless brake lines; which also make the pedal feel better and stronger. Performance brake pads (green stuff, hawk), and ifyou really want to dish out some money (if you plan on bringing it to a track), a Brembo kit. Although the effects are minimal at best, lowering springs and front diffusers will help. the lower your car is, with more downforce, the better handling you will have. Another huge factor in performance is weight, which makes or brakes a lot of cars out there. Carbon fiber parts cost a lot, but they will cut down on weight. Another overlooked factor are your tires. tires make a world of difference. You can really feel the difference in grip just by changing the tires to something more sticky, like Toyo Proxes, (which i put on my 98 328is), they really bring your car to life on the twisty back roads!
***Another thing I forgot to add: If you are willing to cheat the law a little bit, magnaflow high flow catalytic converters gained my M5 an extra 8 Hp to the wheels, with the stock exhaust behind it. In order to keep your check engine lights off though, you need to do a little custom work to cheat the O2 sensors.
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