I have the Extra 300 with a DA50 and Slimline Pitts muffler. It isn't really that loud. I also have a second DA on a Double Vision and that one has the standard DA muffler for the 50. It is a lot louder than the slimeline Pitts type muffler. One of the guys I fly with has a Double Vision on a Chip Hyde Quiet pipe and it is significanly quieter on the ground than my two DA50's but It can get loud in the air if you let the prop rip. Just my opinion but I think the Slimline Pitts would be my choice of the the three options so long as you are not flying around ripping the prop all day long.