Ok everybody, you're probably sick to death about hearing about the brullen headers already, but I just got mine installed today and I thought I would post my impressions.
First off is the finish quality of the header. I've seen a lot of people complaining about the quality of the welds on these headers. Mine weren't exactly a work of art either, but there wasn't any spatter or any other welding related blemishes to be seen anywhere on the header. The ceramic coating was uniform and in good shape with no holidays or scratches in the coating.
Next: Installation. The shop got the header on with no problems, no signs of exhaust leaks or anything else. Two things that were noteworthy, the primary on one cylinder is EXTREMELY close to the oil filter on my car (~.25"). Maybe this will prove to be a problem, maybe not. The other thing is that I have a custom skidplate made of HDPE that could not be refitted due to the size of the secondary tubes. Now, my plate is exceptionally large compared to most and is mounted to a custom cross member behind tranny, so this probably won't be any trouble for any of you eithegs
Performance Gains: Since I got an underdrive pulley installed on the car at the same time, and I don't have a G-Tech or a four wheel drive dyno or any sort of baseline to compare against, I can't honestly give you any real feedback on performance gains. The car does rev noticably more freely now, the redline comes up a whole heck of a lot faster than it did, but whether this is due to the header or the pulley I know not. The butt dyno says its faster, but is it actually? *shrugs* who knows?
The sound with the header on is quite phenomenal. The exhaust tone is a bit raspier, and it is noticably louder. Not put the neighbourhood on red alert loud, but the combination of stromung midpipe and muffler and header makes for beautiful music indeed. The noise is intrusive inside the car, but not to the point of requiring earplugs or anything. At the top end of the tach, the noise turns into this metallic snarl that is really rather appealing sounding. You can also hear a bit of a hissing sound inside the car, which from what I have read is normal with these things.
Overall, I'm quite happy with the purchase. The quality of the headers was excellent, and there were no problems with the install at all. haven't had the header on the car long enough to see if I'm gonna throw a CEL or anything. But so far I'm very impressed. Wish I had some numbers to back up perceived performance gain, but alas I don't own a AWD dyno.