9XL, har har har (that'll confuse him). My 9xl had more than enough speed & power on 4s lipo with correct gearing- it'll run coller than the 8XL too with slightly longer runtime.

Yea 9xl is fine I ran that on 4s in my ofna violator buggy for half the summer it rocked and ran at about 150deg (with mikes motor clamp heat sink).