BMW’s new Z4 roadster which is due to arrive next year as the 2010 model, will grow in both size and price.

After the car was spotted we can see that the car will have a similar shape to the current Z4 but will feature a new folding hard top.

The hardtop provides more safety but it is a lot heavier and causes less boot space. The decision was also made easier by Mazda and Mercedes both having hard top vehicles.

The tail lights look like they have been swapped with the larger ones from the 6-series and the car has a more pronounced grille. The BMW Z4 2010 model also seems to look a bit wider.

The engine should include both a twin-turbo engine and a straight six naturally aspirated engine. The flagship M Roadster is most likely to get a high-performance turbo engine with around 350bhp.

Price and auto insurance quotes aren’t known yet on this model

The spy video can be viewed below.