Z3 3.0L performance enhancement

Hi fellow Bimmers :rofl:
I purchased a 2001 Z3 roadster with a 3.0L motor (powerplant for the BMW hardcore fans) a few months ago.
I am looking at possible enhancements in order to boost my 3.0L when the basic warranty expires in 2 months.
I am wrong by saying that there is not much available on the aftermarket ? I have not found much that would make for a sigbificant power increase for my 3.0L. Is it because the 3.0L is already tune for performance by BMW or is there not enough 3.0L on the market?

Thanks for the feedback