Suzuki Club UK

I believe its around 52mm, but bigger the better as you don't wanna restrict the airflow to the intake.

So how about if i came off the air box feed with 2" then stepped it up to 3" then put in a 90degree metal bend out the wing then a short section of 3" pipe to a 45degree metal bend up the door pillar then a lentght of 3" with the intake grill on top?

That would work i reckon.

2" and 3" silicone hose that is.

i would try and get most of the snorkel done in metal pipe work and then use rubber/silicone bends etc but That to me sounds like your way would work.