Things to look for when buying an mk2 gti. help me?

I am ready to buy a new car and i have a found a fantastic looking 1989 16v dohc VW GTI. I'm very excited for the chance to get it. I love the mk2 style, im a big vintage guy and i love having a car that not many other people driving around have, a car i am very proud to own and can show off to car enthusiasts like myself. I havent been to the car yet, and am a little scared about the age and the fact the mileage was not stated with the sale post of the GTI. Other than that i would really appreciate some pointers on things i need to look for specifically when buying a 23 year old VW GTI. By all means it looks great online, and the owner seems to know what he is doing so that is all well and good. I want to make sure i get a great deal and a great car that is in fantastic shape. Fantastic shape as 23 year old cars go. Thanks all. If anyone could help me out im much appreciated.