I would consider getting a used lrp sxx v1 or v2 tc spec (or comp). V1 units are being sold as low as $80 and with the upgrade board are as good any sxx. It literally just got replaced by the flow and I bet would be unnoticeable (except the flow is nice looking lol)

7.5t would be A LOT of motor for a buggy and if your new maybe too much. With 8.5t I can clear the huge tabletop double at the wcrc 2013 reedy layout I don't know what size doubles your trying to clear but a good 17.5t geared right is usually only 1-2seconds behind mod guys in the indoor tracks. If you insist on mod try 8.5-9.5t

I have always used Novak motors but am loving the lrp x12 octa 8.5 I recently picked up after trying my buddies. Ditched my 17.5 real quick lol. Very smooth and plenty of punch. The x20 I hear is even quicker but I haven't used one.