I've got a '91 GTi with 164k on the clock. But it's averaging about 37-38mpg, uses little oil, is 100% reliable, sounds smooth, idles nicely etc. Basically it's been very well maintained engine wise, religiously well serviced and had a full swap of all engine gaskets and surfaces skimmed etc about 7k ago. It's doing about 60miles per day and is yet to even so much as stutter once - fingers crossed. Shame the previous owner f**ked with the suspension...
Like others have said, assuming the car has been well looked after and not skimped on then I can't see any reason to worry about millage if it's structurally sound etc.