As far as engine performance, it’s starting to come along. Computer upgrades can yield +40hp and +80ft lbs (unitronics) and there are a few others out there. The CR 2.0 engine is rather new ('09+ TDI engine) so development is in the works. There are a couple of companys that make catback exhaust systems and intakes now too. It’s not going to make it any kind of dragster but I’d say 14’s would be attainable.
Mods in other areas as far as body, suspension, wheels, lighting, stereo/electronics, etc its just like any of the other gas models so those are all readily accessible.