Just thought I'd post up the following as it is relevant to the hesitation issue - it's a possible solution involving a small modification, so not everyone will like it.
My 2.2 had mild hesitation (or I was good at driving around it, whichever!).
Previously, I found that freer flowing exhausts helped. I also found that the Mangos original Mod 4 induction (without their injection pressure change) made a big improvement (twin cone filter), almost completely eliminating the hesitation.
After the Mangos' Mod 4 twin cone (with possible rust issues) was replaced by Mangos with a smaller K&N 70mm ID single cone filter, the hesitation came back and became quite noticeable. Probably worse than the stock airbox now that I think about it. The K&N 70mm ID (ID = Internal Diameter) is quite a small cone and is only rated for 160bhp by K&N, whatever that means.
I've now replaced the K&N 70mm ID single cone with the much bigger K&N 76mm ID single cone rated for 340 or so bhp. I didn't do a reset of the ECU. Even so, the hesitation has completely dissapeared. (Bear in mind I also have a freer flowing cat back exhaust).
I can feel something which fits with the description of the transition between the "lean" and "normal" fuel modes but it doesn't hesitate or stutter at all, it's a slight change, and smooth.
I like the sound of the induction, but it is louder, so though many may like it, some may not.
There is some debate as to whether there is an increase in power or not, personally I think the 2.2 benefits slightly in the torque stakes with this mod as the car feels a bit lighter. But then again maybe it is simply because the hesitation is cured - perhaps these are simply two sides of the same coin. General consensus in the thread below seems to be that the 2.2 benefits whereas there's ess certainty on the 3.2.
Cost of parts was about £55, namely K&N 76mm ID single cone filter and Samco 76mm alloy joiner on the Demon Tweaks website, you can probably get them elsewhere too. Incidentally, one of the guys used the alloy joiner that came with the Mangos Mod 4 Mk2 (the one they fitted with the K&N 70mm ID single cone filter) and that seems to work fine too, saving about £10 on the alloy joiner.
There's a thread here including fitting instructions anyway: http://www.alfaowner.com/Forum/tunin...ing-rusty.html
You can read in that thread that after the small Mangos Mod 4 MkII 70mm ID single cone was fitted, some of the 3.2s developed bad hesitation and many users went back to the stock air box - but they don't have the 2.2 hesitation issue to consider so it's a slightly different situation for them.
The 2.2 and 3.2 seem to react slightly differently to induction changes anyway, and I suppose that shouldn't be a surprise. I still suspect that the reason the 2.2 had hesitation is that it seems to come out of the factory with exactly the same air box as the 3.2. Surely exactly the same induction set up can't be perfect for both engines, when the number of cylinders is different and they consume quite different volumes of fuel and therefore air?