I've got a 2.4 SW (Lusso) remapped by Alfatune (DPF removed etc.)
First, I agree about the sound
,never thought I'd say that about a diesel. Personally I think the 5 cylinder growl is about the best you can get from an inline oil burner.
Second it's not so much the ~250bhp it's the crushing torque it now has that is fantastic
Turns the car into a perfect tourer (recently did 1000 miles to south of France and back and it was a pleasure to drive).
Power is always available between 2k and 4.5k rpm. Overtaking is swift and safe.
I was originally waivering between the 1.9 and the 2.4, I think you can tell that I'm happy which way I decided. IMHO it would be a shame to have such a beautiful car that didn't have the "go" to match the "show".
As for reliability, well, both the 1.9 and the 2.4 have their known issues. I figured that getting the DPF removed and the EGR disabled as part of the remap would take out a couple of the most common problems people seem to find
BTW the Alfatune and AHM remap and DPF removal are the same, they worked on it jointly AFAIK
Hope that helps