I am running stock BME mufflers and they don't seem that loud, but then again I like em loud.
As for care and feeding. Use a quality oil, run it a tad rich for the first couple of gallons, baffle it well, treat it like any other gas engine out there and you will be rewarded with many hours of fun flying. That's until you plant it, but then you get to buy a new toy (plane) to play with.
If you have not purchased this engine yet, wait a month or so and the new 115 will be out.