Having owned a plethora of Duramax trucks the past 7 years, I've owned 'programmers' for each, and the market for such items is flooded. You simply plug the programmer into the OBD2 port, and answer some questions. I also had one on a Boss 302 I just got rid of. On a stock 360hp Duramax engine, you LITERALLY can choose from an honest+ 90hp all the way to +300hp. Obviously you gotta rebuild your trans with hi-po internals if you choose above +120hp, but that's not my point. My point is, why hasn't any company released the same thing for the 335D? I realize there's a lot of shops out there that make a killing on mapping ECUs, but they can survive with these things on the market. As most people know, a map made for YOUR particular car is going to be more efficient than a pre-loaded map on a programmer, and in fact, these programmers make it easier for the techs to remap your ECU(the Mustang tuners use 'em almost exclusively). Either way, having the ability to do everything from adding hp, firming up shifts, calibrating your speedo for over-size tires, raising the rev-limiter(if you want to), changing or eliminating your top speed limiter, and best of all, putting it back to stock in 2 minutes for when you take the car in for service. Heck...some of these programmers even come as a package that has a plethora of electronic guages on the screen, which allows you to view (usually) 4 items at once. i.e boost, EGT, water temp, oil temp, voltage, fuel pressure etc...you simply choose the 4 you wanna monitor at any given time, and you get a graphic on the screen that mimics actual guages. Of course for all this to happen you need to keep the thing plugged into your OBD port, but as usual you simply unplug and remove it when you take the car in.
I had a Chevy HD 3500 dually crew cab 4wd, which was lifted 6" and had 35" tires. With a programmer, turbo-back exhaust(turbo's often quiet down the exhaust noise to the point where no muffler(s) are needed, and cars next to you can't tell otherwise), and cold air intake. That truck weighed almost 9,000 pounds, and it pulled 13.6s in the 1/4.
With the car(the US 'D') now being in it's 3rd model year, I figured companies would have flooded the market with these things by now. Unfortunatley all I've seen is one piece that you install inline somewhere, and it's no-where as accomodating as the ones for diesel pickups. Could be 'cuz the market for diesel trucks here is a LOT bigger than it is for diesel BMWs, but that doesn't excuse why Euro companies haven't done it. In Euroland, diesel's are more common than gas-burners I'm told..
I know people are scared about BMW being aware that the ECU's been 'tampered' with, and thereby canceling their warranties, but FEDERAL LAW mandates that if a breakdown occurs and the dealer or manufacturer blames it on a mod the owner did, he burden of proof that this is actually what happened IS ON THE DEALER/MANUFACTURER. They cannot deny warranty coverage simply because you 'modded' your car. Of course you want to use a product produced by a company with a good repuation-and hopefully one that stands behind breakdowns caused by their unit(s), as if you do experience a breakdown caused by your pogrammer, it IS your responsibility.
Just my $.02