I just put on a Dynomax Super Turbo 17747. The body is 20". They do not offer stainless.
I replaced the tail pipe with stainless. I used a 2 1/2" and welded it to the stock tip to match. The stock size is about 2". The shop bent up a piece to match the stock curves. I stayed with 2 1/4 on the muffler to minimize the sound.
The sound is less than my Power Vault I, which had grown too loud. I tried a Flowmax and I found it much too loud. I hit a resonance at 2500 rpm.
Roy