As you may already know, I had the Dinan S package on my beloved 328i. Let me tell you it was fantastic. None of that boy-racer nonsense with the loud pipes or showy bodywork. The addition of the cold air intake, the free flow exhaust, the strut tower bar, and the enhanced engine software didn't turn the 328i into an M3, mind you, but it opened up the mid range of the power band and tightened up the turn-in ever so slightly. Not that the stock 328i was anemic, but in comparison to the Dinan S it seemed to get bogged down in the middle of the rev range. The Dinan package made everything I loved about my 328i better living up to their credo of "performance without sacrifice".
Now, they've released their software upgrade for the N54 engine. There is an S1 and S2 variant of the Dinan software so you can choose the level of boost increase your comfortable with. The choices are sick or insane. To put this into perspective, a Porsche 911 comes off the production line with 345HP and will base out at just a hair over $75,000. With options you'll easily be able to ratchet that number way up, but same goes for BMW. Weighing in at a lanky 3,439 pounds that's roughly a power to weight ratio of 9.97#/HP.
Now, the 135i bases out at $34,900. I know, the likelihood of paying the base price for a BMW is about the same as, well, paying the base price on a Porsche. Tack on $2,000 for the Dinan S2 software and that brings you up to $36,900. A whopping $38,700 less than the Porsche. The S2 software brings the HP rating of the 135i to 384, which is 39 more than the current 911. Tipping the scales at 3,373 pounds the Dinan 135i achieves a power to weight ratio of 8.78#/HP. That's almost a pound less per horsepower than the 911 is lugging around. Think about that. Absolutely insane.
If Dinan is able to put this power to the ground in the same manner as their other products, without sacrifice, then this is pretty much a no brainer. Grab yourself a 135i, 335i, or 535i and drop in the Dinan software. Unless your local competition is driving a Bugatti Veyron you'll most likely smoke them. Plus, the money you save over getting the slower 911 will be enough to buy another Dinan S2 135i.