[HardcoreZ28]

Like most of the posts above stated the rust from the suspension is basically normal, won't eat through those thick parts for a long, long time, and shouldn't spread to the body.

That being said...if you're still paranoid, want the protection, or just for cosmetic reasons I would suggest the POR-15 route. That's all I ever use in my shop. Knock off any loose rust and paint right over the other stuff. This paint needs something to bite into. Give it 2 good coats with a brush, then buy a cheap can of black spray paint and shoot it all with 1 coat while the last coat of POR is still tacky. POR-15 is UV sensative and will fade out over a few months time. This final spray paint coat gives you a lasting shade of black of your choice. You can probably do all of your rear suspension for under $50 and a couple hours of your time.