They still follow roughly the same logic, though now the last pair of digits are a "performance category" that is only nominally related to the actual displacement. Thus we have the 2.0 l turbo-4 in the 320i (180 HP), the (much better tuned) 2.0 l turbo-4 in the 328i (240 HP), and the 3.0 liter turbo-6 in the 340i (340 HP). In the previous generation, the 328i put out 230 HP from a naturally-aspirated 6, and the 335i did 300 HP from a turbo-6. With the slight bump in power, they bumped the nomenclature to match.
Of course, it's all marketing spin and BS, but at least it's still internally consistent.