Keith: that begs the question; are is the Cobra setup $185 louder than the OEM.
The cobra slip on is significantly louder than the OEM. Many guys complain that the Cobra slip on is too loud! I actually like it, not loud like a Harley but you won't sneak up on anyone. I Had the slashdowns and went back to the Cobra slip on, too much low end torque lost with the slash downs. The so called cobra "power port" between them doesn't act like a 2 into 1 as they claim. Now if you want looks and power, the cobra full 2 into 1 is a nice setup.
The slashdowns are loud but I find the slip on has a bigger beefier tone.
Tons of youtube videos of before and after with various cobra exhaust systems
Right now I have the Cobra Slip on, and am very happy.
Also with the stock muffler removed, you will here all the loud popping and backfiring the stock muffler hid due to the factory lean mixture. So the only way to fix that is to add a fuel tuner, or even better get the ECU re-flashed by Ivan's Performance products.
Just a word of warning if you decide the get the ECU re-flashed, the bike will ride and run significantly different since the ignition timing, fuel mapping, throttle mapping and fuel cut have been changed. This means the bike will run BETTER in every way imaginable.
Do you need it , no. But the cost of the re-flash is about the same or a tad less than a fuel tuner, and it it fixes all the EPA crap that makes the bike not run as it should.
But if you change from the factory exhaust, slip on or full, you will have the backfiring and popping and the only way to stop it is with a fuel tuner, or the ECU flash.