Spied: BMW Z9? (updated)

(Updated) Spy photographers have snapped photos of a new BMW roadster in testing on public roads in Munich. After some debate, the general consensus in the spy community now is that this vehicle is the forthcoming Z9 -- a successor to the BMW Z8 and a competitor to the Mercedes SL-Class.

Originally thought to be the next-generation Z4, closer inspection suggests that this could be BMW's SL-fighter. This prototype is clearly larger than today's Z4, but that also supports earlier reports that the next-gen Z4 would be growing up a bit to make room for an entry-level Z2 roadster.

The most noteworthy details on this prototype are the side windows--a glass-to-glass like that of the Mercedes SL. Is that enough of a clue to prove this is the Z9? Quite possibly, especially when taking into account the slim, sleek convertible roof that appears to be a fake canvas top glued to a retractable hard roof that's hidden beneath. Consider that the Z9 is aimed squarely at the tin-topped SL, and is reportedly similarly equipped, and the clues further point to this as the Z9. Gallery after the jump...