Didn't see your post. I'm aware of three, two ZT's and one R75V8. Straight forward to fit, loose most of your boot space and worth doing if you plan to do alot of miles as the payback is limited. Some stories of it giving slightly better performance, but debatable.
Sorry I'm in the "It's a V8 so what if it drinks" camp. My everyday ride is a diesel averaging 43 to the gal, so no guilt