60 MPH seems realistic. If it works out that it can go even faster, I can move up from the 14T bell. I put long slots in the chassis to accomidate any size clutch bell. The spur however is stuck at 51T and there are no options there (OFNA Ultra Diff). I'm currently going to use tires with a 3" OD (From a Super Nitro RS4). I could bump up the outside diameter of the tires and go faster too.

60 is a lot faster than most might think.