Super Racing Medalion has stainless pipes, Racing Medalion does not. Generally with Tanabe if it has "super" in the name that means it's the all-stainless version.

Both forms of the RM and N1 are loud as hell to me, make sure you're a loud exhaust person before you buy any of them. My personal fav Tanabe is the Super Hyper Medallion; stainless pipes, not too overly agressive look or sound but still not stock-quiet like an A'PEXi WS or something.

I'm sure you can find the loud exhaust person thread, it's become legendary by now.