On the projector lens- I got the glass one with the halo you pictured above. One of them came cracked but I found it was easy to work with the seller on that, espescially since I only needed 1.
The H4 bulb mounting was pretty straigforward, but I had to add a screw to hold the extra weight of the Hi/Lo HID bulb and rubber cover it came with wouldn't fit. I found that the reflector didn't exactly square with the lens either- it's a little bit crooked but not extemely obvious. The LED halo is not like the high end LED halo- it's 2-4 leds following the outside rim of the lens. It looks cool, but is totally washed out by the HID brilliance. Same with the little city light. Wire them seperately so you can enjoy the look when the headlight is off.
As far as fitting it goes: I strongly doubt I would have fit the lens and longer HID bulb into the stock CB550F housing, but I have a somewhat deeper chromed shell (I can't recall what it was from, another model 550, I think), so it just made it. The circumference of the projector lens was a bit smaller than the stock bulb, so I made up the difference with slices of fuel hose. It was a bit of a process but, since the thicknes of the bulb seam (where the retaining ring clamps on) was right, it was just a matter of centering it, so the rubber worked nicely and everything is tight.
Overall, I'm pleased with the look and the brightness of the DDM kit, but I'm not done tweaking the light output and not entirely thrilled with the projector lens I got. There aren't a lot of choices though, so I'm going to try to make this work without blinding oncoming traffic.
One thing I was glad I did was putting in a relay and a switch to turn off the headlight. Starting is much easier now.
