to know everything about your car from a manufacturing standpoint, look at this site... http://www.bmw-z1.com/VIN/VINdecode-e.cgi
punch in the last 7 digits of the VIN of your car, and it will give you all the specifics about your particular car!
As for performance, these cars are very accepting of performance enhancements if done properly. The first one that most people here would recommend is a quality aftermarket ECU to open the engine up. It will boost your HP and Torque and perhaps raise the rev limit significantly! Just try to feed the car some better octane fuel after that swap (an easy upgrade, and you can feel it immediately!)
Hope this helps and gets you off and running!