You may want to try the quietest version of the Flowmaster muffler. Although they are justly famous for their V8 exhaust systems, they do make them in all sizes and the quietest version is only slightly louder than stock, but pleasantly so.

I have not used them on an Acura, but had very good experience with a Volvo 240 turbo and a 280Z. The increased power on the Volvo was especially noticeable, probably not a huge surprise given the Army tank spec muffler that Volvo used in those days. I also installed one of their louder import mufflers on my son's Celica GT, and it was definitely louder than stock, but just under too loud. Similar to my '68 MGB.

Chuck
Medford, Oregon