duke
I too purchased a used 06 model classic w/Jardines. I had a pretty good popping on decel. I had the dealer load one of the fattest tunes that Triumph has and it helped some but still had the popping.
The Tuneboy thingy is a personal preference. It all depends on what you are looking for out of your bike. If you are the type that likes to tinker with your bikes and like adding or taking away to make the bike yours. Then you might want to look into a Tuneboy.
I first bought a PCIII and installed in my bike and the bike instantly smoothed out and ran like a top. I had already added the GIPro ATRE and the PCIII was the icing on the cake.
But the PC III can't remove the top speed limiter. So I decided to go ahead and get a T/B just for that reason. But if trying to make your Rocket run as fast as it can and then some, a T/B is the only way to go.
But that is just my take on it. Good luck with your bike.
Big T