A muffler is a muffler. The names are designed to sell product, but in truth just about all the "mufflers" are slightly better than exhaust diverters. They knock down the noise a little, but only a little. It takes cans or tuned exhaust systems to truly reduce noise levels.

As for supporting the muffler with an aditional bracket, it's a very good idea and could save you re-tapping the exhaust flange threads or replacing a head entirely. I heartily recommend it.

Oh, patience is a virtue. 20 minutes from question to the next inquiry isn't really very long Less than an hour for an answer is doing pretty good.