Quick and dirty way to keep exhaust looking good.
http://picasaweb.google.com/merc2dogs/Bike#5063305879708807362
I've got almost 5 years on that exhaust in that pic. I was painting it every spring which was a real pain. I could use a repaint, but still looks reasonably nice, it's still better than it used to be with only one season on it.(seat was a temp just to ride it while building another, so no laughing!)
Install the exhaust, let it get a slight coat of rust, then brush it down and spray it with phosphoric acid rust conversion spray, (most auto parts have it)
Once it dries, you can either leave it 'as-is' or spray it with 1500 degree ceramic paint, which evens out the color a little better. Without painting it's a semi-gloss black (depends primarily on how smooth it was before spraying)
With those headers, I do have to touch up some stone chips right in front where the tire throws up rocks and dirt,but it's a ten minute job instead of a two day, tear off, sand, wash, dry, paint, re-install, so I'm happy
Ken.