What size throttle body can it be upgraded too?

The size of the throttle body you can upgrade to depends on your specific vehicle make and model, as well as any accompanying modifications to the engine. Generally, aftermarket throttle bodies range from 70mm to 102mm in diameter. It's essential to ensure that the new throttle body is compatible with your intake system and that your engine can handle the increased airflow without causing issues. Always consult manufacturer specifications or a professional for the best results.