Not E36 specific, just happens to be a common choice in the Northeast. There are multiple classes racing at the same time (look on the door below the number for ‘JP’ or ‘CM’, etc). The different classes allow different mods. Anything with P at the end is Prepared, and allows limited bolt ons basically. M at the end is Mod and allows almost anything you can think of. S is for stock - heavy cars with full interior and minimal mods.