I bought the silver bilsteins and it appears they are uncoated aluminum. The outsides are white all over with corrosion.
I was going to take them out to install coil spacers, so Ill be adding a couple coats of catalyzed clear urethane after I take a wire brush to them.
If youre repainting steel-bodied shocks, Id sand off all the paint and rust and use a zinc etch primer under the color and clear.

 

Can you explain what this is and where you can get it (catalyzed clear urethane )

 

Its just regular clear paint.. but when its catalyzed by adding a hardener to the paint it becomes solvent resistant. Rattle can clear is not catalyzed paint so it will come off if you get fuel or engine degreaser on it.
Youd need a compressor and sprayer outfit to do this. You mix the paint and spray it before its pot life is over and it hardens.
so youd need to purchase urethane clear along with the catalyst, or hardener.
you can get the stuff cheap as dirt on ebay. Good name-brand paints will cost a lot more.

 

Sorry to tell you this, but your information is wrong.
When I ordered my Bilsteins, I called them and they said the valving is identical in both. Only difference is the 5100s are for lifted trucks, besides the color.
If you dont believe me give Bilstein a call.\ Heck look on the Bilstein website.

Its funny how you call the Yellow ones cheaper ($6.00 difference in price from yellow to the zinc ones). I have had mine on my truck for 3 Chicago winters and they look brand new. I put 25,000-35,000 miles on a year, and Chicago is notorious for using extra salt on the roads.

 

Well, I stand corrected. I thought the valving felt softer. But that was just me I supposed. And when I said "cheaper", I didn't mean to insinuate that they are cheap, just less money to pay for them.

 

So is this the same stuff they us at a body shop that they call base coat clear coat minus the base coat .