Jim Lomas pipes/Athena 421 compatibility question

I have an Athena 421 kit for my RZ350 and will need pipes. Would like to use the Lomas GP twin exit pipes, but keep reading that adapters for the exhaust flange are needed.

Anyone have any experience with this combo? All the info i can find either leads to dead forum links or pictures that Photobucket deleted. My emails to Lomas and a couple distributors have gone unanswered.

Any info is appreciated.

 

Meant to put this in the 2 stroke forum.

 

Cont Jim at Fast from the past