I usually get the ofna 3 shoe flywheels (they make an OS specific one) they sit a bit further back to give you more clearance.

bearings are 5x10's, I've been running the "budget" bocas ($1 a piece) for about 3 gallons/5 months. Same set still work perfect

make sure to get the traxxas BB kit (there are a few to choose from) because it comes with the throttle bellcrank standoff you need. We will custom make your linkage at my house.