A tuned,properly sized, right length pipe would not need baffles. However size constraints coupled with the "cool look" make this just about impossible to obtain with the off the shelf exhaust in every day use. To make up for this we add baffles, etc, to help get our exhaust more suited for our particular engine. Though usually not perfect it may add to performance and be a suitable compromise. Some makers have realized this and make two different versions of the same exhaust, one for smaller engines, and one for larger engines.
You can spend a lot of time, energy, and money on dyno time looking for "the best pipe" and when you get it you probably won't like the looks or the sound. Remember pipes are usually tuned for a specific RPM range!!! If you want a pipe that will more than likely get the best all around performance, take your check book and call RB Racing. Be forewarned they are expensive, but they do work. Oh and listen to what they tell you as they are too busy to spend too much time on the phone wit window shoppers. You've been warned!!! Hope this helps

 

Thanks to all for the responses, it gives me a bit to think about over the winter.
Spanner and 2006FLST could you provide a link to the washer trick, I would like to have a look at this after all never enough tools in the box. After reviewing the comments received I have concluded (at least for the time being) that the current set-up provides enough back pressure. The bike has a true dual set-up with mufflers marked “Illegal for street use” not sure what brand they are but they do have a plate with three holes at the end that I believe (correct me if I am wrong) should provide all the back pressure I need. I am going to try the torque cones this spring to see if they help low end torque which could be better especially when the bike is loaded.
97HeritageSpringer I get almost the same sound and it is quite a treat when you see the heads turn at the shop as the lads with the $20+K invested try and figure out how to get their ride to sound like the old girl potato, potato, potato.

 

http://www.nightrider.com/biketech/exhaust.htm

 

The true "potato" idle is pretty low, like 600 RPM. You don't want your bike idling below 1K. Evos don't like it below 1K. Not enough oil flow. It ain't a pan head.