Later ones had flexi up-pipe, early ones had solid, which is where the issues were on the early ones. Mine have been on for 6 months+. They went straight on and have not caused any problems.

 

I have got the version 2 Gruppe-s headers with the Helix flexi up-pipe, fitted straight away and no blowing up-pipe gasket I also paid extra for the Jet Hot Coating so that I didn't have to wrap them

I have got nothing but praise for them so far, they have still got the burble at low RPM and sounds like a large bike at high RPM

Headers, up-pipe, Jet Hot Coating, shipping and duty £430 to my door. I'm so pleased with the service I got from Max at Gruppe-s I have just placed another order with his company.

I do not know what gains I got from the headers because I also fitted quite a few other parts at the same time and I'm still waiting to arrange a mapping session with Mr F when I finally get my Apexi Power FC.

Colin.