[Finnster]

I think its really about he power level you want. 4S is good power, BB nitro-like speeds with more TQ and accel. Very drivable and reasonable on the drivelines.

6S on a 1Y is like an A-bomb. Over the top power and likely to cause a driveline meltdown if left in the wrong hands. Extreme care is advised.

So it comes down to what you want. If 45mph is fine, and looking for trackable speeds, then go w/ 4S. If you want a out of control driveline shredding wheelie monster, then go all out on 6S.