I was thinking that maybe you could make it so that you have 1 and a half minuets to customize your Jetskis/ Karts using your Garage mod. Also, (I don't know if you already did this) but make it so that the vehicles support the stereo add-on. Anyway, this is turning out excellent and the Jetskis are really smooth, and feel like a speedkart.
Hopefully you're also going to post the group photo in this thread (because I'm an ego-cigarette)