It's hard to factor in economic impacts without a lot of data and understanding, and I doubt anybody -- even the experts -- has a perfect handle on it. So I don't even want to hypothesize about that.
I am coming from an 08 Honda S2000, and got wind of the E89 Z4 when I saw one on the highway recently and couldn't take my eyes off it. Without doubt, styling is one of it's biggest qualities. Upon driving the Z4, my first impressions were that it was heavy, expensive, shifted a bit vaguely, and handled vaguely compared to the S2000. And then I came around to the realization that it was really like butter in most respects, worth the money, and much more refined than the S2000 (raw handling and shift quality aside, as the S2K wins there hands down).
So my own experience tells me that the Z4 is a bit of a niche vehicle and you have to truly "discover it" to really appreciate what it brings to the table, and then be willing to pay for it. The build quality justifies the cost. But it's not the best sports car out there or even the best sports oriented roadster. I think the cadre of buyers who really appreciate this car lies at a very specific crossroads of tastes, sport/comfort tradeoffs, expectations, and incomes. That is a small pool of car shoppers.
What I did find troubling was that 6-spd manual Z4s are hard to find, and dealer inventory is biased to high-priced loaded automatic cars -- totally opposite of what I'd expect of a true roadster. Dealers could be hampering sales as much as anything else. I decided to wait and order a Z4 with the equipment I wanted and at a more reasonable cost. But not everyone wants to wait 6-8 weeks for their new car. In fact, I went for the S2000 last time around because I got frustrated at the lack of 6-spd BMWs available for evaluation/purchase in 2007.
One thing in BMW's favor is that they are masters at mixed production, and can likely handle small quantities of Z4s mixed in with other production without too much trouble. In contrast, Honda canned the S2000 when US sales dropped below 3000 a year (this after a nearly 10 year run). I think they could no longer justify the dedicated production facility and specialized production process that was taking a potential factory away from higher demand vehicles. BMW is in a slightly different boat, and I think they can make the E89 work in smaller quantities just fine.
Last edited by skier219; 11-02-2010 at 08:33 PM.