Hi mate, I personally have a V3 STI 555 V/Ltd, and I can tell you they are great cars althought they are heavy on the juice. As long as there is plenty of service history with the car you'll be ok What mileage etc is on the one you are looking at, has it been modified. Me personally I always look for a standard car but as long as the work has been caried out properly it'll be ok.If you are at all unsure there are always RAC or AA inspections, ok it might seem an extra expense at the time but it could save you a fortune later on in repairs and if there is any small things wrong with the car it can be used as a bargaining tool.
Good luck with the search mate and welcome to the forum.
Also I'm sure there will be wiser people along in a minute, Squiggle by the way cheers for the MAF advice, worked a treat.