Has anyone used this combo? I'm trying to figure out my risers as I have a lead on manifolds. I would like to keep my mufflers. I have standard b1 dimensions. I think I need these magnum risers but i don't know if they will line up. I see some old shorty ones but I can't find listing's on any. My mufflers are staggered in out heights. My original manifolds had a 3" spacer for the risers. also what are the seaward series ones? Are they interchangeable?