I checked online and found my nearest VW dealer was open 'til 5:00 Saturday. Drove over there to get the gaskets and found the parts department had closed at 1:00. Drove home and did the job anyway. I would have preferred to have a new metal gasket, as it took some scrubbing with a Scotchbrite pad to get it smooth enough to be sure it wouldn't leak, but it was not a problem.
Here are my comments:
1. Some of the how-to discussions say disconnect the coolant lines from the exhaust cooler and either clamp them or position them high enough so they don't spill coolant. This isn't necessary. Once the exhaust cooler has been untethered from its moorings, there's plenty of flex and length in the coolant lines just to pull it up out of the way and tie it there with string.
2. I chose to use the "redneck" method, with a plumber's torch and compressed air to burn out the residue. After watching several YouTube videos of the procedure, I determined there's no need to put a wet towel on the outside of the manifold while doing this, and in fact, the wet towel can keep the process from working completely.
This turned out to be easy, and fun!
3. It took some experiment to find the best positions for the torch and compressed air. It worked best to keep the torch off to the side enough so the compressed air didn't blow it out, but where it still kept the residue ignited.
It worked best to hold the compressed air nozzle back away from the intake opening a little to get the strongest burn with the least amount of smoke. This was a bit tricky, as the best position for the air also meant there was a plume of flame shooting back towards my hands. I did the job with bare hands and didn't get burned, but it would have been safer with gloves.
4. After the burnout was complete, I blew compressed air on the manifold awhile to start cooling it slowly. Then I misted it very lightly with a fine garden hose spray, let the mist sizzle off the manifold, did it again, etc. until it was cool to the touch. I would not quench a hot manifold by immersing it directly in water.
5. At this point, there was no remaining buildup of residue except a very thin crust in one or two small areas at the engine block ports. I scraped this off with my pocket knife.
6. Then I felt inside the manifold and found it was clean down to the metal surface, but there were tiny sandy granules of black grit that could be rubbed off. I flushed the inside with the garden hose and compressed air and rubbed off as much as I could reach with my fingers, but there was still some remaining, so I tried some chemicals.
7. First I tried BrakeKleen, which dissolved some but not all of the grit. Carburetor cleaner might have been better, but I didn't have any.
Then I tried filling the manifold with oven cleaner, sloshing it around and letting it soak a few minutes. By orienting the openings so they were above most of the body of the manifold, I was able to get the manifold full, with the oven cleaner in contact with pretty much all the inside surface. After leaving it to work awhile, I washed it out with the garden hose.
This worked really well, leaving shiny metal in much of the inside, and black but otherwise clean and grit-free metal in the areas towards the four openings that connect to the engine block.
8. Then I cleaned out the EGR/anti-shudder valve body. This was easy with a pocket knife and attention to detail to get all the surfaces cleared down to metal, blowing out any loose crumbs with compressed air.
After putting everything back together, I took a test drive and found there was a noticeable improvement in response through the power curve. Especially, at about 3400 rpm, it would continue to accelerate in third gear up a hill I use for testing, whereas before I cleaned the manifold, it would level off unless I shifted.
This manifold wasn't very dirty. There was hardly any residue inside the body of the manifold or near the ports to the engine block. There was some buildup at the EGR end of the manifold, but still a large opening, nothing like some of the pictures that have been posted.
Even though this car was running really well, I had decided to clean the manifold based on its mileage (154K). After seeing how little residue there was, I thought there might not be any noticeable effect from cleaning, but I was pleasantly surprised.