Re: GTV Alloys
The GTV 17" teledials are the way to go, although they are difficult to get hold of (there are pattern wheels out there that look similar, and look good). The offset for these wheels is ET30.5, so they'll really look good on your GTV.
When you get to 147/156 wheels you begin to have problems with the offset. 17" teledials from a 147/156 GTA will be ok as you have a 2.0 car, so the smaller calipers on your GTV will not foul the wheels. I think you will have problems with the 16" 147/156 teledials though, these may well foul the calipers, even on a 2.0 car, and will look wrong anyway as the offset will bring them too far into the wheel arch. You could fit 10mm spacers, but I don't think it's really worth it.
Hope that helps.