I just wanted to say how pleased I am with the Akrapovic full system my wife and I fitted to her 954 (had to say that lest she reads this
As our budget didn't stretch to a powercommander I was worried that that with the HTEV valve removed it would run rough and that the powerband would be full of holes. On the contrary - it runs smoother than stock and the surging that used to occur at low rpm has gone!
It is not only smoother but the power now builds progressively and predictably off the bottom. Sure, it's a bit flat until 4000rpm but then again it was never very strong down low anyway and the new smooth build up from low rpm is far more preferable than the way it was stock.
Otherwise, from 4000rpm on it feels every bit as strong as before but with better throttle response - and the top end is more than most riders would ever need (Akrapovic claim 141hp as opposed to 131hp stock).
Did I say it also sounds great? Not too loud either.
In summary, I don't think anyone needs to worry about fitting a full system without a powercommander. I'm sure it would probably run better still with a powercommander - but my advice to someone trying to decide whether to first buy a powercommander or an exhaust system would be - "Get the exhaust!"
The next thing we're getting is a Scotts damper. Only after that, might I look at getting a powercommander.
Finally, I just want to say I was very impressed with the fit and finish of the "evolution" (titanium) system - not to mention how light it is. Thumbs up to Akrapovic for producing a great product! (Pronounced Ah Kra Po Vich