Ohhhh I wish I had a chance to make a suggestion with respect to a muffler choice.
On my 85 gsl I removed the stock muffler and put an Anza duel tipped "muffler". Similar to those used on older Italian supper cars. It was perfect. At idle and up to about 3.5k rpm it had that British roadster sound. Perfect for around town. As you went above 3.5k it started to transition to that sound only a rotary can make. By 4k you were full on rotary and it went on to redline like this. Mind you it was not that nasty high pitched make your ears bleed sound. But a lower tone that was just spectacular.
I will go see if my google fu can find me the unit I used and post it up.