We are known for a few mods that we developed for the BRM, BEW and BHW; the 04-06(really, 07)PD engine improvements. Our mods will keep the engine going for hundreds of thousands of miles.
We started into the CBEA and CJAA and fortunately, we found it questionable to pursue upgrades for the common rail engines. That decision to nix upgrades for the CR was made just before the Diesel Gate Scandal. I am so glad we did not pour money into that project, only to have 80+% disappear from our shores.
Initially, our feeling was the emission controls were going to get us into trouble. Since they were virtually turned off, they didn't. I think now, that spectre is going to raise it's ugly head. For one thing, the DPF is hard on a relatively weak Borg Warner Turbo. Sure, we can change the turbo out for something like the Garrett PD 140, but in spite of claims of some of the horsepower numbers we hear coming out of this engine, I feel the common rail should be left in it's stock form. I find the cylinder head itself, a bit 'dainty'. I would not call it 'robust'.
The other thing we have noted from the engines we have seen is by dropping the engine oil weight to 5-30 (we think it's because of CAPA standards; to increase fuel economy), the cylinder walls are suffering. There are several engines we've taken apart to find the classic 200k as we have seen in previous year engines, 'Still can see the cross-hatch' from original hones marks, in the common rail, they have disappeared. So, there is an additional wear issue with the comparative higher heat and thinner oil in the common rail. My thought is to revert to a more practical 5-40 weight oil. And don't believe the temp gauge on the dash. It's a liar. We have seen plenty of them show up on our door with the temp running above 205f. We don't like it.
As for the BRM, there are three things we are constantly addressing with that engine.
1) Premature cam wear. We have shown great longevity with our upgrade cams and our track record with our modified cam, cam bearings and reusable bolts have given us an enviable reputation for longevity.
2) The EGR cooler has a nasty habit of leaking at a poorly devised butterfly valve, which only operates, generally, for about the first 2 minutes of the engine's warm-up. Then, seemingly, it's only purpose is to wear the butterfly valve's shaft and lose all your boost. We have created a very good cure for that.
3) The most common transmission installed it the BRM is the 6-speed DSG automatic transmission. The big issue with that is the dual-mass flywheel must occasionally be replaced, usually in about 180-250k, depending on how much stop and go traffic you meet. The job entails about $400 worth of parts and 3 hrs of a mechanic's time. The later version flywheel seems to have great life-expectancy.
The best way to keep the flywheel from being replaced is DON'T IDLE, at least, not any more than you have to. Don't do 'warm-ups', as the diesel will hardly do what I consider 'warming' on a cold day, at idle. Get in, start the engine and DRIVE. If you are going to be idling for 5 minutes, shut it off. Your flywheel will thank you and it will live longer.
Personally, the BRM is not perfect, but it's not bad, either. Feed it clean fuel. Change the oil with the BEST oil you can find and when needed, consider our upgrades and mods. It will live a very long time.