Feigao heat problems.

[BrianG]

IF you are happy with ~36mph, the relatively low kv of 1600 should be fine. I wouldn't gear much higher though for the reasons I stated earlier.

$150 to change the diff ratio? Wow, that's a bit pricey! Have you checked the ebay chopshops, or is that the retail price? 3.3:1 diff ratio is typically used for buggies, so it makes sense now. Truggies typically use a 4.3:1 ratio which allows more flexibility with spur/pinion gearing. And since you didn't say, I assume there are no larger spurs available?