It's not just a "bit of smoke" though, is it? Much as I like the way my 2.4 delivers power the smoke that a non-DPF car generates is highly toxic in an urban environment and, IMO, much worse than the extra CO2 generated by a regen. I'm happy to put up with the poorer fuel consumption to run a non-smokey car.
It could be just "a bit of smoke". Depends how you are driving it, and how it is mapped of course. You could map it to be stoichometric and it would be smoke free other than a puff at spool-up, and it would be more fuel efficient too. OK it wouldn't be quite as powerful but you could outweigh that with a bit more boost. The plumes of smoke are only there due to incomplete combustion, most of which is caused by there being too much fuel injected in the first place. The funny thing is that the only reason they are ran rich in the first place is to chase the big power figures. Diesel is slow burning, so the theory is if you inject more than you need to make sure you burn every last bit of oxygen. But then you're left with a plume of smoke and a power-sapping DPF to counter it! Its madness!
If the DPF system is only fairly reliable while the cars are only a few years old, what are they going to be like when they are 6 and 7 years old? I do like the 159 and I do intend to buy one, probably when you can pick up a 5 or 6 year old 210 model, but I wouldn't have one without disabling the DPF, as it is an inherent flaw in the car as much as it serves a noble goal. Its much the same as the EGR valves are being disabled on the 16v and 20v engines in the 156/147/GT, because they have proved problematic and fundamentally flawed. I'd equate driving a 159 with the DPF to like driving a 147 GTA with the standard diff. Might be OK but it might cost you an arm and a leg if something goes wrong.
DPF technology will improve - maybe the problems are due to the fitting of DPF's to diesel engines that weren't specifically designed to receive the technology. The 2.4 must be getting on for, what, eight years old now since it was originally introduced as a 10v engine.
The 2.4 came out in 1998 in the 156, it was production ready in 1997 so thats 12 years ago, the design must date back to at least '96? Its an old engine really, but Alfa got 25 years from the Busso..