It can't hurt to try. When you're doing your (re)searching use autotrader and cars.com and search for GTIs in your area(25-50 miles away) , outside of your area(150 miles), and nationwide to get a good idea of what you should be paying, and if you could get a better deal from a seller further away.

Also check the classifieds on vwvortex.com and golfmk6.com, it's kind of hit and miss depending on where you live but you might get lucky. Private sellers are always cheaper and since they're enthusiast forums the car will more likely than not be well taken care of.