I was even racing them on Nords...
all i could imagine was up to 50 karts charging round the ring, they do max out in certain areas but as some of the track is uphill its less than you think But they are still great to race round there.
Piddy is another track that's great for the shifter karts. fast and flowing with big banked turns.
in fact most tracks are ok to use them on, they do max out in places so this means its in the twisty bits were you can battle,,
lots of fun both ways..