RTABs are an issue with the E36 if you let them go too long then it can do serious damage. Like DinanM3_S2 said the drivetrain on the E36 is stout about the only issues you will have related to that would be the cooling system and pullies.
Just get a good shop to look it over before you do anything. Also dont over look one just because it has been to the track. These cars are ment to be driven like that.