I can't speak to the MS3 but I have the Meanstreet 800 on my 427 SBC and I love it. Full roller motor, Edelbrock air gap intake. I went with Fitech's fuel command center so I didn;t have to make mods to my tank or mechanical
fuel pump. Tuning was a breeze, this is a street car - I hve about 700 miles on the MS800 so far so good