The UE spider diffs are nothing but the cheaper Ofna/Hobao diffs which comes in eithe 6 or 8 spiders. UE just added their own diff outputs. You can buy them from dinballrc.
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)