There are many sites out there specific to tuning cars, especially the 200SX's which are popular for this usage.  In addition, you can check various auto parts sites such as this one: http://cpwstore.carpartswholesale.com/year_model.php?make_text=nissan&year=1986&model_text=200sx&cat=h
to see various parts which are available to improve performance on your car. Good luck!
CarGrrl