I think the basis of the question is poor. That is: the Z8 and M5 share some mechanical components so we can compare them. Well, then why not compare all cars that have GM parts? Or why not compare the M5 and 530 sedans?
I think better questions would be: Considering the price of a E55 Mercedes, do you think you got a bargain? or Considering the price of a 530i, do you feel you got a bargain? Because there its closer to apples- to apples. And finally: When shopping for a M5 or performance sedan, were you looking for a bargain?
We should also think about how the M5 compares to other performance cars- Porsche, Ferrari, whatever have you. Why limit it to the Z8? Because it has some of the same mechanicals? Other cars have similar performance specs.
Compared to most sports cars, which are inherently limited on space, one could call the M5 a bargain.
However, to call something a bargain I feel that there are 2 ways to look at it. First, it can be relative. Second, you have to have some rationality behind it. Fact of the matter is what you are paying for with the M5 (over standard 5 series) is more feel, better suspension (better for driving feel), better engine (again makes you feel a certain way). Many people who just buy a 540 or a 530 might say, gosh, that M5, what a waste of money. I get the same amenities, the same safety, maybe 80% of the performance, but I dont care. BMW has really expanded their M lineup. I dont know for sure, but Im sure they're making a nice profit off it, and it has to be a nice margin b/c its a lower volume than their other cars. So think of all those components that stay the same and then try the comparison. You could say the 530 is a bargain compared to the M5!
Im not saying those people are right. But then think about those folks. Why buy a 530 over basic A-B trnasportation. Of course, there really is a value to safety, after that though, what did they buy? Point A to point B transportation, which can be had even cheaper.
Point is, once you get beyond taking care of the practical things (a-b, safety) youre left with all kinds of things that are there to help you rationalize a more expensive purchase (GPS, CD changer,bigger wheels, spoilers, etc).
So its easy to see how someone can say- that M5, what a bargain, while someone else says, that M5, what a waste!
The fact that many here own M5s says that they are at least willing to go somewhat extra for that feel. And therefore you could say that that person thinks that feel is a god thing.
Why criticize those who decide to go even further for more of a good thing? Porsche, Ferrari, Aston Martin, whatever. Bottom line, life is too short, if you enjoy driving that Z8 or 996 or 360 and you could afford it then all I can say is congrats and best wishes.
To get back to the thread question: Considering Z8 prices, do you feel you got a bargain? The answer is I cant say. Comparing a sports sedan to a sports car is a very difficult thing to do.
ME