I have an R56S 2008 model, but unfortunately i don't know if this model is called as a N14 or N16 or N18?
Second generation MINIs NOTE: 2nd gen Convertible was released in 2009 in Cooper and Cooper S trim. 2007-2010 R56 and R57 Cooper = N12 (N12B16) Non Turbo 2007-2010 R56S and R57S Cooper S = N14 (N14B16) Turbo 2008-2010 R55 Clubman = N12 (N12B16) Non Turbo 2008-2010 R55S Clubman S = N14 (N14B16) Turbo Read more: http://www.motoringalliance.com/library/all-about-mini-coopers-17/mini-engine-codes-110/#ixzz2sIfqxaAS
Just in case you didn't know where your model fell in the list above, you would have an N14 engine. An easy way to tell, is by looking at the engine. If you open the hood and are able to see the spark plug port and wires, and if you have a MINI logo between the Spark plugs and air box, that's an N14. The N18 has a cover over the engine with a MINI logo on it, that surrounds the oil cap. The cover also blocks you from seeing the spark plug ports and wires, unless you take it off. The differences between the 2 engines are significant, but those are two easy ways to tell the two apart. I attached a picture of the N18 engine, so you can see what it looks like. Hope this helps.