Is "Fat Boy" quieter then....

You won't like it! It hangs very low and has a lot of drone.

A-1 or similar is the way to go... 

I had a fat boy muffler (located between the passenger side valve cover and wheel) and couldn't wait to get rid of it.

Bearable with the top down, but WAY too loud with the top up.

If you want something quieter this is not a good choice.

Actually, why don't you call Henry at IM, he can get you a double muffler set up that gives you a quieter set up... probably the quietest you could get without too much work and it with all the clearance you need.  

I had that setup with a 2110cc and it worked well.  I liked the sound but it was controlled and not offensive. Ray

I have what is said to be a A1 sidewinder, and the can says Magnaflow or some such.  Gives a pretty quiet ride when just cruising, loafing, and a nice  throaty note when you run it up under full throttle.  Folks trailing me on cruises have said they like the way it sounds.  I know I do.  All that said, these cars are noisey under the best of conditions, and so it goes . . .

Thanks to all for replying....I agree the A1 is.....A1, but pricy so for now, I'll try the 'double muffler'. I'm a proud IM replica owner, who is also a proud Porsche 356 and 912 owner...I have to give equal ($) time, to all three ladies, or I will be in trouble....

Have you looked at The "Vintage Speed" exhaust systems?