Mas fotos del nuevo Z9 (no se si ya han aparecido) Here are more pictures of the BMW Z9 caught out testing on the streets - but this is the first time we've seen it with the roof down. It's designed to be a direct rival to the Mercedes SL-Class and the Z9 will feature a folding metal roof like the SL. It's based on the underpinnings of the 6-Series and will sit in size somewhere between the 6-Series and the Z4. The 6-Series platform gives the potential for a number of suitably powerful engines: the 5.0-litre V8 plus, of course, the M6's 5.0 V10. There's room for either under that long bonnet.