Modifying a CSL

[crazy of cookham]

Any ideas what could be done to a CSL in upgrade performance. Sorry not a daft question I know someone who seriously wants to do it. Already derestricted by BMW. Can you squeeze further HP out, or are they already at limit. If so who could you use. Assume work will invalidate warranty. Can you purchase independent insurance backed waranties.
Tks

[crazy of cookham]

I do believe the world is smaller than we think. Thats probably a yes.

[crazy of cookham]

Thanks for the advice. Now I can convince him to get the work done and have some fun with the car.