Thanks for all the help Colin and John
I got a e-mail back from AirBorne Models this was their reply.
The N version has some modification at the exhaust channel area and make it more suitable for mounting short pipes, R is more for stock muffler.
The wings are the same for both R and N version.
They have referred to my request for a wing to their Hong Kong office has shipping from their to Australia should be cheaper
Thanks again for all your help regards Mark