I recon those khe tires go ok hey. just keep them over 80psi and your sweet. its the pressure pushing out from the inside that gives them their strangth. try get the street tyres tho, the park ones suck balls. i ran mine on 130psi and it kicked booty till the beading gave way. WARRENTY!!! XD
BUT for the best tires, i'd say go the maxxis grifters. cheaper, lighter and stronger than the khe's. one khe costs $80 but at For The Riders, you can get a maxxis for $40 i think? or about that. I know i got the 1.85 rear for like $30 cause it was the last one or something. i duno i got lucky but who knows. go have a look in there anyway their the cheapest around