No need for a four link use the stock rear suspenson and add air bags to it, the front you can buy plates that bolt in to mount the bags really the only mod is a c-notch in the back the rest bolts in get a hold of FBI (Fender Bender Intl.) there local here in sacramento but they mail order world wide. Im not really a fan of airbagit.com's stuff
Here is a link
http://www.fbirides.com/