My dad bought an '04 Interstate 27 foot inclosed snowmobile trailer a few days ago. It weighs about 6,500lbs fully loaded with all four mountain sleds in and gear/gas. He insists that he will pull it mostly with is 1998 1/2 ton suburban vortec 350/4L60E instead of my '01 dodge cummins or the '98 C30 dually vortec 454/nv4500 ranch truck that would be perfect. The burb seems to have enough power but it sags fairly bad in the rear and it feels like we are on a boat sometimes if it is a really rough road. It isn't all that bad in good road conditions but something to help it out to make it feel more stable under bad road conditions would be nice, especially up in the mountains in bad weather. Has anyone used the Hellwig helper springs or the roadmaster system? We are looking at those kits in summit. The air bag deal is nice but expensive for a premium setup. What works well guys to help out the rear springs just a little and make it feel a little more stable? Thanks.