I just purchased a 1991 318i and am looking for ways to upgrade all parts of the car in order to achieve maximum performance. Any ideas?

engine swap for maximum performance horsepower and torque wise the m42 engine is not really an engine designed for big power. i have a 1991 318is and i could care less about top speed right now i am more into the handling of the vehicle. If that is the performance you are after you can follow what i did and get some eibach prokit springs, bilstein shock absorbers,(Or spend a whole crap load more for coilovers) eibach sway bar front and rear and racing dynamics stress bar. As well as higher performance wheels i went with BBS RGR wheels for better rubebr and larger Brembo brakes cross-drilled and slotted. Eventually i will swap the engine with an S54 and hopefully turbocharge it but we will see that.