Developing an all-new iteration of a beloved car is no easy feat. Improving on the existing strengths while introducing as few new weaknesses as possible and at the same time improving value and performance is as tough a balancing act as you're likely to find. But BMW thinks it's done the job with the new Z4 and has released this behind-the-scenes look at how it did it.

The video depicts a prototype, completely unmasked, on a suspension simulator that's able to compress weeks of driving into hours of testing. That high-tech bit of kit, plus a lot of other machines, computers, simulators and highly educated people are what came together to yield the final product.

Toward the end, the roadster's new hard top is shown off and though we don't get the detail we'd like, it does reveal the general look of the car in a more candid environment than the press photos from the official reveal.

2009 BMW Z4 convertible