If you’re gonna spend the dollars to do a true dual exhaust, stay with small diameter tubing and you should be fine. Also, do a dyno run before and after and I’ll help you with the co$t of the dyno time. New, smaller diametet PowerVaults (shipping NEXT week) would be great in a dual setup.
Or, ou could always do a single PV muffler with dual tips out the back - I do agree duals look better!