25. 1976 Porsche 924
There were high expectations for the 924 when it hit the market. The car was supposed to be a revolutionary Porsche model that deviated from the tried and true design. The problem was that the design was almost too revolutionary and there were still a lot of kinks to be worked out. The 924 was notoriously unreliable to say the least, and this caused a lot of headaches for owners. The car would routinely have issues such as overheating and electrical failures. When you are spending this kind of money on an exotic car, the last thing that you want is to be broken down on the side of the road.
Porsche tried to rectify these design flaws early on, but it was too late. The 924 is a car that should be avoided at all costs. Later Porsche models were much more reliable and fun to drive, whereas the 924 just remains a money pit.