Unelss you want to spend ~$150 on the HPI suspension kit, this will be your only option:
http://www3.towerhobbies.com/cgi-bin...4&I=LXPZN1&P=K
I know it's Integy, and it sucks, but several others and myself have been using these without ANY major issues. There are some fitment issues sometimes, but once you get past that they work great.
SH Z-Car, Custom Crawler, 8s Savage,
12s XTM XLB 1/7 buggy,
4wd 4-link rear/IFS Pro4 truck,
Custom Hyper 10 Short Course,
Belt-Drive Mammoth ST 1/8 truggy, 4s 17.5 MM Pro HPI Blitz