BMW Repair: Tire Rotating & Air FIlter, stock air filter, cold air intake

Question
I have a 2004 325i (sports package):

1) I was thinking of replacing my stock air filter with a K&N filter for better sound and the xtra hp. What are your thoughts on this product?

2) I have dunlop 17" sp sport 2000e tires. How often should i rotate them and how (i.e. back left to front right, etc?)?

Thanks a ton, great service!

Answer
The air filter itself isn't going to do that much of anything. If you want more noise and a little more power, consider a cold air intake kit. they'll give more sound but not enough power to notice the difference. your BMW dealer could also give you a problem regarding warranty on the vehicle. BMW says not to rotate the tires because the car has a 50/50 front to rear balance and that the tires should be balanced only. however, we always rotate and balance tires every 15000 miles. the tires need to be rotated front to back and back to front only, no left and right