I just picked up the Dixis Titanium Exhaust and H pipe from an M5 Board member (thanks!).
The Dixis is 26.4 lbs. The band clamps (not included) are 1.1 lbs. The stock rubber hangers (reused) are 1.3 lbs. That's a total of 28.8 lbs. The stock exhaust is 79.8 lbs. That's a 51.0 lb difference between the Dixis and the stock system.
Here are some pictures. I'll take some video next. Unfortunately, I let the batteries run out on my HD camcorder.
Here's a look at the stock main cats attached to the headers, sometimes called the precats. They're metal matrix, but high cell-count:
Here are the main cats, sometimes called the secondary:
The first thing that had to be done is cutting the stock pipe. The pipe was cut, then the cut was smoothed, so that it doesn't impede exhaust flow.
Here's the Dixis titanium exhaust:
Close-up of the welds. With titanium, because it is so hard to bend, the shaper turns are welded, while the shallower ones are mandrel bent.
Single wall, flame treated dual tips, 80mm each:
Band clamps are used to connect the exhaust to the stock "section 1" pipes, since the diameters are exactly the same:
It uses an H pipe balancing tube instead of an X pipe:
Here's another look at the tips on the car:
Sound wise, the exhaust is quieter than I expected for such small mufflers, especially with titanium.
Idle is a little louder than stock, though it has a fuller presence. There's absolutely NO drone at all, which is AWESOME. I cannot stand resonance at all, especially with a luxury oriented vehicle.
With low throttle, it's close to stock volumes inside the car, though a bit louder outside. Cruising is comfortable and quiet.
With the mid-throttle, you definitely hear more of the exhaust, though not a lot.
With heavy throttle, or with the throttle completely buried, you can definitely hear the exhaust. There's a far better balance between the induction noise, engine noise, and the exhaust note. At high RPM's, there's a smooth, ramped up scream. Surprisingly, it's not raspy at all, despite the removal of the resonator. There's no crackle or tinny sounding buzz to the exhaust note at all, just a building crescendo to redline.
Overall, I love it. I like how it's reasonably quiet still, because that allows me to increase the noise with headers or high flow cats. If it's too loud to begin with, swapping cats will make it unbearably loud.