I think with a car this old there is no guarantee of reliability whatever the cost (excepting if a full full rebuild has been done of course).
£1500 will get you a good example but you will need to keep putting money in to maintain it. Mine is due some respraying and new wheels right now lol!
My 8v was a similar price to what you are looking at. To give you an idea in 2 years i have done some wheel bearings, bushes, suspension once, brake disks, pads, brake pipes, tyres, a CV joint, temp sensor, coil and i think thats it! I do have some seriously harsh roads round here though which does account for some wear. I am reckoning about £400 a year on repairs roughly.
Anyway i have rambled on enough!!
