No first hand, as I am not a fan of Ti for offroad use, and at $990 (after 15% off) it is just plain too spendy for my taste's.
From what I have read on various forums, everyone in the know seems to find the same thing, nothing else comes close. There is a lot of combined LC4 experience, dyno runs, etc. over at the Monomaniacs site, and they seem pretty strong in their recomendation of the Akrapovic system. I would take a hard look at what the guys at Monomaniacs and KTMtalk have posted concerning this system, no one seems to be complaining, it really seems to make these bikes come alive.
My point is primarily that adding a slip on for power IMHO is a waste of time, unless you just do not want to spend the time to modify the OEM Supertrap. (There is restriction in both the headpipes and in the silencer, but the silencers are pretty easy to open up.) I personally could not stand the OEM Supertrap, I did not want to spend time modifying it, and I liked the looks and sound of the SXC Supermoto silencer, so that is what I went with, but power gains were really not what I was looking for, or what I found with the addition of this silencer. I did the airbox mod, carb jetting and added the SXC Supermoto silencer all at the same time, so it is hard to say what made the biggest contribution, but based on the dyno runs, and more so my experience with my Duke II, I feel strongly that the airbox and jetting gave the biggest improvements, although all three are required to get the most out of each individual change.
Österreichische Motorräder und deutsche Autos. Wie wundervoll kann das Leben sein