[A Snake]

Before I actually read your post, I would have said "why would you want it quiet?"

I too live in a quiet neighborhood, but my neighbors just smiled when I drove into the driveway and it was loud enough to set off car alarms 100 feet away.

As to how to quiet it down, the stainless might look good but it is actually very often louder than plain steel. It seems to have a more piercing sound.

You might look into "supertraps" like racecars use. With these you can add or subtract layers to change the noise level. The down side is that the quieter it is the more back pressure there is, which is true of any exhaust system.

Just my thoughts

Al