This is a happy accident, the purple paint i used wasn't as metallic as i was expecting but i kinda love the G1/Movie hybrid look.
It was one i've had in my paint box for years that i don't remember buying, Citadel Liche Purple. Presumably i'd gotten it from Games Workshop at some point.
This reminds me of the ps3 dotm game where you could customize characters by changing their colors and everyone proceeded to make Shockwave extra purple. Very nice!
What I find compelling about this G1 inspired paint job is that it is entirely plausible that Shockwave looked that pristine and pretty on Cybertron before the war required him to shift from a buttoned down mad scientist to a Head Beast Master. Nice work.