Until last week, I had the Fullsac X-Pipe and their 2" CVO PowerCore baffles on my FLHXSE3. It is a
very good quality, ceramic-coated 2-1-2 pipe - probably the best on the market - and lots of folks on here use it. It makes very good power, and the 2" baffles are fairly quiet compared to many other brands. They have a nice low tone, especially if you leave the packing in the cans around them. You can hear the audio easily. V&H also makes an "X" pipe style header system that a lot of flocks use.
A 2-1 pipe like the D&D Fat Cat will make more power than either a 2-1-2 pipe, or true duals - because of the large collector and better scavenging and exhaust velocity.
I don't have any direct experience with Rineharts, but many of my riding friends have them. Rinehart also makes a 2-1-2 pipe, and a 2-1 pipe - but they sell a lot of their True Dual systems. True duals have no crossover, and thus no cross-cylinder scavenging. They will not make the raw power of a 2-1, or even a 2-1-2 pipe - but many people like them because of their distinctive exhaust note. Without any crossover, you hear each cylinder more distinctly than with a crossover-type pipe, and they generally do not idle as smoothly as crossover-type pipes. They look really good, too.
I just installed a Drago's Bike Works
S/C/S-4 2-1 pipe on my bike this week, with a left-side ghost pipe. Drago's pipes are manufactured by Rush Performance, and they are very high quality pipes. I have a Mods thread in the CVO Street Glide section, and around page 20 starts the discussion of the S/C/S-4 i just installed. Early riding indicates that is a winner. It has long, straight 1 3/4" equal-length headers going into a 2.55' collector, and then into the 4" Dragula muffler with a 2.5" core. I also installed Cometic MLS .030" head gaskets to give my Andrews 54H cams more squish to work with - so it's hard to tell how much of the improved zip comes from the 2-1 pipe and how much comes from the Cometics. The S/C/S-4 is pretty loud - but has packing in the muffler that eliminates most of the higher-frequency tones, and this makes the pipe have a very deep bellow. There is also a good amount of "reversion roar" when you back off the throttle. I like the sound of the S/C/S-4 a LOT. It is similar to the sound of the D&D Fat Cat. It's pretty loud - but you won't have any problems hearing your 400W stereo!
Here's a link to a video I made today of the sound of the S/C/S-4 on my bike. The pipe sounds a LOT better in person than it does in this video.
http://www.flickr.com/photos/northgeorgiahawg/6968273963/in/photostreamHope this helps...