Firstly- has anyone every used the CatCams cams in their YB?

Or, could someone in the know tell me the difference between the AB07 & the CatCams Fast Road Inlet
http://www.catcams.co.uk/acatalog/Ford_YB_Cosworth.html

This would be on a std engine, t34, 500cooler, siemans55s

CheeRS Fraser