As one who has owned a 2011 D only since May 5, 2012, I can hardly speak from experience on this. But I have been also pondering a JBD, a Renntech flash, or an Evolve flash. Am sorta leaning toward the Evolve flash now that a speed shop in Northern VA is a newly-minted Evolve account. But that choice is all a matter of personal preferences in the end I guess since I'm not rich enough to sample each of them.
Back to the intake carbon build-up issue, I have a couple of observations:
1. When I went to my first BMW CCA social in NoVA, the guy sitting next to me owned a speed shop out near Reston. Somewhere in the conversation he warned me about watching for this problem around about 40k mileage. So I just parked the info away. Now that this forum has surfaced at least a couple of cases of this problem, it is probably real enough depending on one's driving style and probably a lot of other factors.
2. What I would be curious about is whether there is any difference in experiencing this carbon buildup problem between those who have a tune and who do not have a tune and also both have at least 50k miles on their machine.
3. Whether or not "blowing the carbon out" regularly as in the old days conventional wisdom makes any difference or not, it seems intuitively that the people who want to install a tune may in fact be putting the pedal to the metal more often.
As soon as I get around to it, I plan to do the tune anyway, but I'm more worried about the dealer messing with the warranty than I am about the impact on carbon buildup. I guess that is also why guys like the JBD add-on so they can take it off prior to having work done. The Evolve guy told me he would reflash it for $100 labor (no freebies) if the dealer writes over it.
Quaife LSD w/VAC finned diff cover, M3 Rear SF Bushings, M3 sways & M3 OEM Susp Front/Rear Cmpnt Kits ('cept strut brace), GC Caster/Camber Plates, AC Schnitzer M3 Sport Springs, JRZ RS1 dampers, JBD 100%, Goodrich SS brake lines, non-stggrd APEX ARC-8 18" wheels with Nitto Motivo tires (winter OEM 17" wheels and Blizzak LM-25).