1991 318is Chassis question

Stupid quwstion - My son has a 1991 318is. We want to replace the brakes and such. How do we know if it is a M30 or M36 chassis?

Its actually E30 or E36 chassis. And you have an E30 chassis with the M10 engine. Check out http://www.europeancarweb.com/features/0402ec_bmwcodes/ for more info.

Thanks for your help