Look out for....
rotten exhausts
budget tyres
stone chipped front ends
curbed alloys and bubbling finish on alloys
if you can buy a car that has had the standard stereo replaced already that'll save you money as the standard stereo has several common problems that render it useless (imo)
Don't bother holding out for a model with the standard birds eye sat nav as ive read it's not up to scratch.
other than that look out for standard wear items such as worn bushes, worn discs and pads, worn tyre tread, worn leather interior and scuffed door cards (these cars are difficult to get in and out of if you are tall and the door card suffers)
the engines are pretty reliable, obviously look for a car with a full service history
some cars suffer with clicky rear axles, but nothing a dab of grease and a confident DIY'er can't sort though.
Rays alloys were an option on pre '06 cars
GT spec is nice as it adds cruise control, heated leather seats, "Bose" stereo components
Good luck with your search, there are always loads for sale, test drive a few to get a feel for the cars first.