Thanks again for your suggestions and input guys, very helpful and I'm learning a lot
I think what I'll do is wait until the car arrives and have my upgrade people measure the clearances for me while they're doing their works. Hopefully get a better feel for how much space I have to play with and give me an idea of what sizes to go for.
Will keep looking through other threads and see if I can find a few listed combinations that people have which work for some more info in the meantime as well!