Gloss all day long. As above, what colour is the car?
If it's blue, green or black I wouldn't bother, it'll look pants... Silver and Red I'd probably do and Yellow could look kinda funky...
It's down to your taste though
FYI - my mate wrapped his BMW in this weird matt gun-metal stuff and he said its an absolute pig to clean and it didn't stay matt for very long... it sort of developed smooth, glossy patches from washing it. Avoid IMO