I've read the discussions on Zero rust & Rust bullet & POR they all sound like they are good solution to rust, but which one will stand up best on suspension components with the abuse they get from gravel, rocks, sand, possums etc.?
go around some garage sales where old buggers live and see if you can pick up a never opened can of real old high lead content black enamel and put that on it...It'll be on there when you die from old age. I hit a garage sale when a neighbor was moving and bought six quarts of Manowar spar varnish for 50¢ a can. the cans were rusty on the outside but never opened so I had my truck bed varnised for four years for 1/4 the price of one can of the stuff.
I used marine enamel,brushed it on good and smooth.haha.Its tough stuf and a fraction of the price of powdercoat.Plus I don't think powdercoat works on rusty steel?.......Shiny
Powder coat was/is my first choice, but I'm not sure about baking the tie rod ends, whether they could be damaged,(of course I know I have to remove the rubber boots...
A cheap alternative (powder coating can get expensive) is to clean/prime parts, spray on a coupla coats of 3M chip guard, then Zero-rust or other tough enamel. Almost bulletproof.
POR has no UV protection, so if the parts are in the sun don't use it. Don't know about the other two.