I had this same problem too, my tanabe G power medallion muffler got all crusted out and rattled. I shopped around and there aren't too many choices if you want name brand. I ended up with a real APEX N1, if you don't want to cut and weld then 5zigen makes a fireball axle back which should work.

And no tanabe does not make the hyper medallion muffler only...i wanted that and it does not exist. There may be a RM muffler but i don't think it will be real tanabe.