I've got a glacier white 200 and had roof wrapped in gloss black in February.
I'd say go for it! Worst case scenario, if you don't like it, it can just be peeled off. In my humble opinion, it still looks friggin awesome, especially with the black speedline alloys. I'll take some photos at the weekend, if you're still interested.
Regarding which parts to get done, the guy who did mine (auto-pro motorsport Deeside, Cheshire - highly reccommended) said that he could do whatever I wanted eg. leave the roof rack bits or not, same with the top of the boot. I had the roof rack bits covered but left the top of the boot white - partly because I have a white elia/k-tech sprint rear spoiler.