I have to agree, the glorified sticker doesn't look that nice and painting your calipers isn't really a hard job, you could have it done before lunchtime on a weekend. Also, the 100HP is pretty rare, getting picky about whether potential cars have the Pandemonium pack or not probably isn't worth it, or that was my opinion when buying one anyway.
As for the stereo, I find the standard stereo to be a lot worse than the one in the 2010 Fiesta I used to drive. There's a lot less bass and it's can't handle nearly the same volume before distorting horribly. If I were to buy another 100HP, I'd make sure it had the uprated stereo.
The sunroof is a matter of personal opinion, but I think they're a waste of time (especially with climate control as standard on the 100HP). It seems that as cars get older, their sunroofs leak, irrespective of make or model; more effort than they're worth.
As for traction control, it's pretty much irrelevant whether you want it or not. I doubt you'll be able to find a 100HP in the UK with it specced.