So I'm curious what makes the exhaust sound, the muffler, baffles, or a little bit of both? I love the sound of the older screaming eagle II slip on mufflers (I had them on an 03) and I'm looking to recreate sound that on my 2008. I found some used screaming eagles for cheap, but they don't have the baffles. If I buy replacement baffles from cycle shack or other aftermarket baffles, will it have that same sound (good rumble without being too loud) or will the baffle primarily influence the sound?

 

I suspect the answer is a bit of both. The shape and size of the muffler will be one influence, the baffles another. In the good ole days a muffler could be completely empty, nothing inside it at all, the performance of the exhaust being totally dependent upon it's shape. Interestingly that didn't mean that it was certain to be very noisy, because they often had a fairly small outlet. Adding a baffle must increase the complexity of getting the exhaust to perform well.

An aftermarket baffle has got to be worth a try, as an economical way of trying to get what you want.

 

Mufflers are interesting animals.
Generally the larger the muffler , the deeper the tone.
This is why most bagger bikes sound so cool and deep with 4" diameter , long mufflers.
Drag pipes usually have a high sound with a crack to them as the volume is very small.
As the explosive gasses enter the muffler , they must be slowed down and controlled before they exit.
A large hole (baffle) keeps the exit velocity higher and produces more high RPM power.
A smaller hole (baffle) slows the velocity and produces more low to mid range torque.
The more you bend and divert the gasses (baffle) the quieter it becomes.
Stock mufflers slow and redirect the gasses so much they become quiet and hamper available flow and power generally suffers.
You have a unique opportunity to experiment with the screamin eagle mufflers you have now.
Give a look here.
http://www.jpcycles.com/exhaust-baffles
If your mufflers are 3" , there are dozens of possibilities to install generic baffles open to you.
The good rumble without being loud is what I'm searching for myself.
If you look at rush mufflers , they can be had from 1.75" to 2.5" baffles.
They offer a 1.5" baffle for quieter sound , but not as a complete unit.
If you have to guess at the size , go smaller and work your way up as the they get louder as they get bigger.
Just a few thoughts.
Mick

 

Another factor is the engine!

Your 03 was carbed.

Your 08 is EFI.

There were also different cams in them.

Even with the same exact muffler and baffle they are going to sound different.