I have to think there are notable suspension tuning differences between the Crossfire and MB SLK 320 in only because the SLK was fitted with 16" wheels (7" wide front, 8" wide rears) while the Crossfire has 18" x 7.5" front and 19" x 9" out back. The additional unsprung weight with the Crossfire's rolling stock may well overtax the SLK spec suspension bits, even if they would technically fit.

While I can't say with 100% certainty that I am correct in the above assumption, it just sounds logical to me.