Hello folks! I decided that I needed to join this forum to help me understand my new car. I got it last summer and it has been in the garage mostly. It is a 1991 300ZXTT. I am kind of new to this modification stuff so I got some questions. What is the largest size wheel/tire I can put on the stock frame? Next question. The former owner had done some mods: Dual Stillen exhaust, a JWT ECU and a P.O.P. upgrade. What is the P.O.P. upgrade? Lastly does anyone have any suggestions on how to mod the engine to increase power that is economical? Thanks for all your input!