I haven't seen mention of this here, so I thought I'd throw it out:
http://www.grandprixgreensboro.com/
They currently have only the 6.5HP Sodi karts, but they are the newer chassis style than what Rush Hour or G-Force or Victory Lane have. The newer chassis has a little bit better grip compared to the older one, but that's mitigated at this track by the fact that they didn't strip *all* of the sealer and thus the surface is still a bit slippery. I personally like that, particularly with the 6.5's as it means there are generally more brake zones.
Add to that their track design, and you have a winner even with "only" 6.5HP karts. I think the track design is one of the better around. It's way better, IMHO, than Rush Hour, and as good or better than Victory Lane. The facility is nice and they have a LOT of karts so they can have folks staged and ready to run the next race as soon as the last kart pulls in from the previous one.
It's about one minute off of I-40 just on this side of the airport exit in Greensboro. It's probably 15 minutes closer than Rush Hour for me. I'd definitely rather brave Greensboro traffic at rush hour than Raleigh, too, so that's a big plus.
Anyway, pricing is about the same as all the tracks. Get the $15 membership and buy races 5 at a time for $15 each is pretty much the best deal. They are 8 minute stints, just like the rest of the tracks like this.
--Donnie