E36 M3 suspension clearances

[dahermann@xxxxxxxxxxxx]

I'm considering the purchase of a 1996 M3 that has 18" BBS wheels.  It is a second owner car and the current owner thinks it has been lowered approximately one inch.  I'd like to verify that since I track my cars and don't want to bottom it out.  The Bentley manuals lists the clearances (edge of fender to bottom of wheel) for 17" wheels on the M3 at:

Front standard: 23.03"
Front sport:    22.05"
Rear sport:     21.26"

Would it be as easy as adding one half inch to these clearances for the additional inch in diameter for 18" wheels?

Also, I didn't realize the M3 was available in different suspensions.  Is there a specific trim level for the lower suspension?

tia,

dan hermann

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