Originally Posted by BaLAnCe17
whats the stock differential in a 98 or any 328is
If it is a manual I believe it's a 2.91 or 2.93 (not sure about the last number but it doesn't matter).
If it is an automatic it's a 3.91.
A 96 to 99 m3 has a 3.23 which is a great swap option for a manual 328i or 328is.
I saw that in another forum you mentioned that you purchased a set of Bav Auto headers. IMO this is a much better alternative to the intake manifold. Comparable HP gains w/o the loss of low end torque.