Sam,
The biggest problem is lack of maintenance over a period of time. These motors aren't cheap to run but if serviced regularly and looked after when they need new parts, most of them will return a good service to the owner.
The other problem is a lack of knowledge at the local garage, these motors do require specialist care and attention.
What happens on a large scale is that people try to get by with running a big car that they really can not afford but were tempted by a low initial purchase price and the fact that when parked up on a forecourt, they look stunning all polished up. These motors don't rust unless they have had an accident and it hasn't been repaired properly.
Service wise, nothing is cheap. GTO's are well capable of sitting at speeds well in excess of 150 mph all day, or at least until the next full tank.
They are heavy and demanding on the brakes which are not cheap for a decent replacement set. Tyres aren't cheap for quality ones, obviously the price varies according to wheel size.
The list goes on but if these parts were replaced with decent items when they were needed and the engine/transmission etc was serviced on time, they would be in better condition now.
It's just that people buy them, run them into the ground because they can't afford them and then sell them on, and the cycle continues.
I have seen them come into our workshop in such a bad way that if they were animals, the kindest thing to do would be to put them down.
That said, there are plenty out there which have had absolutely thousands spent on them and treated like a part of the family, these do however, demand a premium price when/if they are ever sold. There are bargains too.
You are welcome to call me if you need help, we build, service, maintain and upgrade these cars, and others for a living but i am more than happy to help people too. :bigsmile: