Help with new project.

Just threw something in the speed calculator, wanna clear a few things up. About how big is the average buggy tire? About how much does a converted buggy weigh?

I selected 43/13 for the diff ratio,
direct spur 1 to 1
46t spur
then I am not sure what a good starting point is so I dropped in a 16t lol
4s lipo, 14.8 they are about 3.7 a cell right?
I selected a 6xl for a starter pretty much at random.
I also threw in 5 inches even for tire dia. becasue I think 2.2 bugg wheels and tires are about 4.0, not sure though.

Spur/Pinion Reduction Ratio: 2.88 : 1

Total Reduction Ratio : 9.50962 : 1

Tire Circumference (?): 15.71 inches (398.98mm)
Total Motor Speed (?): 41129.2 RPM
Final Vehicle Speed (?): 64.33 MPH (103.34km/h)
Effective speed rate (?): 4.35mph/V (6.98kmh/V)
Calculated Loaded KV value (?): 2779

I figured going over the recommended rpms a little is okay. Wouldnt it cause a little extra heat? I thought the top speed is a little high though. I was only shooting for 50 at best out of this. I think maybe an 8xl would be the ticket.