Counterpoint opinion.
A STOCK RXV will run 19.5 mph.
On most hills, will not slow down much, Probably maintain 15mph.
RXV's commonly have 4x12v batts which are not as good as 8v batts,
but swapping to 6x8v is not that hard and relatively cheep (compared to controller/motor/charger)
Might look at RXV as option as you will be spending about 1/2 to 3/4 the cost of an RXV to upgrade your current ride.
Find someone with an RXV and try it on a hill...
