i have a full bra for my GT. indeed, you need to take car with it; in particular, the paintwork needs to be perfectly clean before fitting it, to avoid scratches. it probably doesn't suit people using the car as a daily driver; for me, i nearly always only drive the GT in fine weather (not rain, let alone snow), and my car is kept pristine in a garage with a car cover between drives.
it also isn't overly attractive.
http://pic20.picturetrail.com/VOL97/467659/9659844/255640847.jpg
move forward a few years, and with my 159, i bought a clear film kit. i am very, very happy with it; a friend gave me tips on applying the bonnet piece (he works with graphics on vehicles), then i applied the rest of it at home.
there are presumably similar kits in the UK, or you can probably order from this place in Queensland, Australia. they have a GT kit (i have thought about applying it to my GT, but meh, i have the bra):
Duco Scratch Online Store:
