X1-CRT 1/8th gearing choice

I was wondering if i should keep the ferris wheelspur gear on my 1/8th CRT? If not, what do ya'll suggest is a good gearing choice with a Feigo 9xl and 4-5s lipo? I'm eventually going to buy a Neu. I'm shooting for 45-50mph, faster if possible.

[skellyo]

4S on a 9XL is going to be hard to do 45-50mph reliably IMO. You'd need a 19T pinion to do 45 on 4S. On 5S, you can go with around a 15T pinion for roughly the same speed. This is based on the stock 62T spur.

Honestly, I think it's a lot to ask of a 9XL to do 45-50mph in a truggy. I think speeds of 35-40mph would be much more in line with keeping temps in a reasonable range.

What motor would be best?