The Hyper Medalion is still on the loud side. If your custom 2.25" piping is in good condition (i.e. no rust), then I'd recommend an 18" long perforated-core Magnaflow resonator and an e•s Tuning Systems universal muffler.

Quiet, with superior flow and no need for silencer inserts like the Apex'i N1.. Very discreet.