Sorry to hear your tales of frustration, its one of the reasons why I generally prefer to buy from private sellers, OK, this can have risks but to be honest I've bought some piles of funk from so called car dealers so due diligence is the name of the game. Over the decades of car purchases I'd say on average I've had better cars from private sellers, besides many cars on forecourts can be PX cars and Auction cars , give me an enthusiastic owner any day.
That being said I generally never follow my own advice

, I can think of a whole host of cars that were bought without test driving other similar cars for comparison because I stupidly and impatiently needed these cars in my life ASAP........TVR CERBERA, CHRYSLER VIPER GTS, EXIGE , PORSCHE TURBO and recently E86 Montego Blue Coupe

..........fortunately the only car I ever purchased that was a complete PUP and NIGHTMARE to own out of the above was .........drum roll....?( wise heads know already)..........was the frigging.......Cerbera.....get cold sweats just thinking about it 25 years later......you couldn't make it up.....I can't recount the whole story now but perhaps I should, but when your speed 6 engine decides to eat itself and spit out metal shards into its sump then returns from TVR BLACKPOOL with a "brand new engine as said Mr Ravenscroft but we're only giving it a 6 month warranty ", to find its your original engine what's just had an engine flush and a few new parts you know you've got a serious problem

The kicker was being told " yes Sir all our new replacement engines have mud and alloy corrosion on them from storage in our yard but we've stamped your original engine numbers on the head and block for your convenience "........ now that's what I call customer service.... :thumbsdown: