Thanks for your warm welcome and good replies.
The wheels of the CSL kit was to small. I bougth the Renaissance BBS wheels set and this was also to small and not best. Thats why i used rims from the Tamiya Celica Gr.5 kit. I removed the inside and replace this with the PE set from Renaissance. This fits perfectly.
The engine is from the Revell M1 procar. The engine in booth cars was very similar.
CSL -> BMW M88
M1 -> BMW M88/1