Hi folks, I have had an E92 335i (N54) for a year now. Was wondering about a few things now that baby's coming up to the 100,000km mark: 1) Is intake cleaning (via walnut blasting) necessary? And if so, where have you done it — and what's the cost? 2) Are there are any gearbox specialists who have experience with DCTs who can be relied on to keep my DCT in tip-top shape? 3) Based on my reading, Stage 1 takes the car to about 400hp and 500Nm. If any of you have done it, how has reliability been? 4) Is it necessary to upgrade the downpipe (to a metal one) + diverter valves if and when I want to take the car to Stage 1? 5) Related to point #4, have you modded your turbos? What is your setup? 6) I was told the fuel filter has about a 150,000 mile (not km) lifespan, and should be left alone until it reaches that milestone or it fails. Is that true?