You could try "muffler silencers" that go into the tailpipe holes. There are many types and prices listed on ebay. I have never used one and cannot say if that method works well or not. You would have to measure the exhaust openings and find what fits. I don't recall any posts on the forum from anyone mentioning they installed silencers.

If it's a Borla or Magnaflow cat back you may be able to find someone on the forum willing to swap their stock exhaust with you. It's a very simple swap out.

I bought my first Magnaflow catback from a guy that said his wife found it too loud. He ended up putting his stock exhaust back on.