air box pipe size
 

Hello there, I have just recently fitted an inlet pipe to my classic MY00 turbo, I needed to trim the air box pipe which attaches to the inlet, but after lifting bonnet up, I noticed that it doesn't look so secure.
I was looking on graham goode site, and they have either a 90mm, or 80mm, does anyone know which size I need? thanks.

Oh by the way, i have standard air box, no fancy induction due to MAF on this year isnt so good.