angrchair
Quarry Creeper
You could try out Rust-Oleum "painters Touch "2X" UltraCover paint - it's paint and primer in one and says on the can that it bonds to plastic, for indoor or outdoor use - so it should be reasonably durable.
You WILL be touching it up fairly often after big tumbles, though. But - you could just use a silver paint pen for that!
I'm about to build a heavyweight Bomber as well - using a mix of SSD axle housings and some Vanquish parts - and my hard GMade springs just got lost in the damn mail!
ooh there is even a satin aluminum and Aluminum general purpose color choice. Sucks about your springs :/