Theres a bit of history on these, 80mm throughout most of their length pipes.
There are 2 designs
a.with an aluminium billet/reducer
b.a pipe made without an aluminium reducer(the pipe itself reduces in diameter close to the turbo)
Ill summarise the way I think it went as follows.
Badger Bill guy developed a pipe with an aluminium billet/reducer at the turbo end.
Some companies started to clone this and BB ,probably rightly ,got a bit peeved .
At the same time,the "cloners" also started to introduce an all silicone version.This version had no aluminium reducer at the turbo end .It merely had a silicon pipe that narrowed at the turbo end.(It was also cheaper to make)
At this time BB opinioned that the all silicone pipe was a pos.
The only "good" big TIP was the one he supplied.
Time passed
BB now supplies the two designs,he reckons the all silicone is now ok ,but the aluminium billet is the ultimate .(say £30-50 more for billet version).
I believe the BB versions are 2.2 for the aluminium and 2.3 for the silicone
To complicate things a little BB made some arrangement where he supplies his original aluminium pipe both himself and thru one of the cloners (S+S) maybe ,not sure .
Creative motor sport or cms.. Mondo got an aluminium billet pipe from ..It didnt fit very well

If you check them out on ebay or their home site,there isnt much difference in price between either design but after Mondos experience, I certainly wasnt going for a billet one of theirs.
I went for a cms all silicone jobbie..about £100 fits fine but..like quite a few others the big TIP can cause surge .
Im in the process of getting that corrected by Wak atm .