Going over 60 MPH has NOTHING to do with how the car is driven. The car is not even to 2500 RPM in 6th at 60.
It is how it is driven TO 60 that you have to worry about.
But a nice E36 M3 will set you back around $20K, leaving you with $10K to mod and maintain.
'95 Alpine M3 LTW
'00 Dakar M Roadster
'02 Topaz M3
Red/White SRF #4 (Chassis 561)