D/W about the rear plate - you'll get used to it, I thought the same thing when I put my slimlines on and a few people also commented that way, in that there is a lot of surrounding space. But I love them now and the way they look so the gap doesn't look odd to me anymore :) When gold is polished and waxed and sparkling believe me, people won't be paying much attention to the space around the numberplates!
Good luck with the parkers too, unless you have very small hands the best bet is to take the front bumper off, which isn't actually as scary as it seems. You just have to be careful when it comes off not to let it go or pull too far because of the fog light cable still being attached, so you just need to unclip that if you want to move the bumper further out of the way. There are a few how-to guides on here, if you do a search they should come up, I'm sure it was Daryl (DJKOR) who made a thread in the Aurion forum that had some pictures in it. I'm at work atm but can have a search for you when I get home tonight.