There is more to the EGR device than most people give credit for.
First, if you don't give a damn about air quality, I'd say go live in a big city like LA, NY, London, or even Phoenix. Places with stagnant air and an inversion layer would disagree that EGR's have no value. Of course, we know particularly, the BRM system breaks down. WE FIX IT! And at a nominal price.
Many ALH owners have a problem with the EGR, when the EGR clogs the intake manifold very badly. A 2 1/4" intake manifold hole with so much carbon built up, you can't put your pinkie in the opening. Sure, we've seen LOTS of them... But with my own 2002 ALH Jetta and near 260,000 miles, I have NEVER cleaned the intake...don't need to. Proper driving habits and keeping the engine in the correct operating RPM range eliminates the problem.
All the driver's who putt around with the engine operating at 1200-1800 rpm are lugging it, damaging rings, wearing out cylinder walls and creating gobs of intake clogging soot. This engine should not be run below 2000 rpm, in my opinion, and actually, should be driven at speed, with the 'sweet spot' at 2500 rpm...highway speeds. We constantly tell drivers, if your upshift puts you below 2,000 rpm, shift back and try again. That technique will improve engine life expectancy and reduce clogged manifolds.
There is another good reason for the EGR system. It lowers head pressure, making the engine peak pressure lower when you don't need the extra air and compression. That can make the engine run more efficiently, with less parasitic drag to create the compression stroke, strange as that may sound. Reduction of unused oxygen in the combustion stroke reduces or eliminates a major pollutant, NOX.
As for the BRM, I rarely see any intake clogged. More likely, the EGR valve will stick and need cleaning about every 50,000 miles or so. Otherwise, you get a reversion effect, where the engine lacks power, then suddenly, around 2200 rpm, it's like you finally turned the turbo on. The EGR valve is stuck open, allowing the boost pressure to go backward down ERG and EGR cooler exhaust path until exhaust pressure builts enough to compensate. Then you get a surge of power, as the boost pressure is now headed the correct direction. Very dependable indicator to clean your EGR valve.
There is the BRM's EGR Cooler butterfly valve problem, which causes as much as 30% of your boost pressure to disappear out the butterfly valve. but overall, the system does it's job, works quite well and the parts, like EGR valve, when they are needed to be replaced, have come down to reasonable pricing.
As for those who delete, I do not expect to change the mind of the 'purist', who thinks his car's pollution does not matter. I still say, "Leave it better than you found it." Removing CATs, EGRs and other emission control devices is not improving air quality. For me, professionally, it's illegal and subject to EPA regulations and huge fines.
So, I will continue to repair the BRM EGR coolers. I believe on average, the butterfly valve, if it does anything, only improves the warm-up time by a couple of minutes. What I do eliminates the loss of boost pressure, while maintaining a functional EGR system and NO CHECK ENGINE LIGHT.
