We at Rug Racers here in the UK have been using these tyres for over a year now on Prima felt GT, and have found them to work very consistently through out the 5 min run with next to no rubber inside the shell. The V2 wheels which fit exstremley well onto the hexes now, and have no issues. These wheels seem to be good for 30 5, min runs, and more.
This is our second year of using the yellow EXP wheel and SWEEP control tyre with great results, and have been giving feedback to the distributor in the UK.
I personally would like to try them on tarmac, but the weather has been against us here in the UK of late, but when I do I will give some feed back on here about them.
Cheers Malc