Another year, another MOT passed with just a couple of minors (rusting brake lines, dodgy OSF wheel bearing) which I'll get sorted in Jan. I also had the CDV removed...
For those who don't know, and I didn't, modern non-M manual BMWs have a fitting in the clutch pipe called a Clutch Delay Valve. Essentially this is a restrictor that won't allow the fluid to flow back too quickly when disengaging the clutch, the idea being it allows for a slower and smother gear change. The downside here is that by doing so it's essentially slipping the clutch every single time you change gear, and heel and toe changes are much harder to do. By removing it you make it like every other car and any jerkiness is purely down to the driver, but you're now able to do very rapid gear changes.
Now, a lot of people complain that the gearbox in the manual 6er is crap, and I'm convinced this is the reason why. Having removed it, changes can now be much smoother and also much snappier, and it's significantly better in feel too. It was a bugger to bleed apparently, but on a drive across to a mate's house to re-bleed it decided to self-bleed and is now perfect. Removal of the CDV takes about half an hour, and you can either just remove the entire valve and pull the metal clutch line over to bridge the gap, or just pop the guts of the valve out using a small punch then replace it back in situ.
For anyone with a roughly 2000 onwards manual BMW (E39 & E46 eras), this is a must-do mod. Go try it, you'll be pleasantly surprised.