I had them and loved them!! they are by FAR the best you can buy (and the most expensive) but you get what you pay for... here are one threads where you can see them on a build.
Castle Neu 1520 on 6S LiPo Powered Gmaxx (Nitro Killer)
Predator with OS .21TM
Supermaxx with Mach .26
Revo with OS .18TZ
Kyosho ST-RR Conversion
Ofna CR with Tekin ESC/Motor (2)