I used one for a few years then gave it to a good friend.
- I would totally disregard the power readings on the display. I had a track bike with an SRM attached, and the numbers rarely coincided (300W on my SRM head unit wasn't 300W on the Cateye display). I never turned the unit on.
Agreed - one of my teammates has an SRM on her Dolan. Looks like the Cateye is optimistic to the tune of 100 - 150W at a full load of approx. 1200W.
- If you do use the numbers, use them as relative measures for each individual machine. This is because the resistance is made by the cable adjusting how close the Eddy Current Resistance Unit thingy was to the other thingy (scientific term). Anyway, 1 cable could be a bit more stretched than the other. The lever is indexed, so if it's not calibrated, then it could be off. Think of an uncalibrated rear derailleur.
Thanks - sounds like at least checking the copper disc for runout and proper clearance would be worth the time.
- If you want numbers maybe try the Kurt Kinetic Road Machine. They have published a power band that is directly related to the speed you turn the trainer. Basically Xmph = Ypower. They even sell a speedometer that displays power.
Our team actually took delivery of a Wattbike about three weeks ago. Everybody sorta is getting a feel for it right now but it should be a good source of reliable data. Unfortunately, we only have one, so seat time for every team member is limited. 
- I would only use them for Sprint type efforts (standing starts, short efforts with negative splits (flip the lever for more resistance), etc...). For longer efforts a normal fluid trainer would be better, especially when using a road bike that way you can dial in the right cadence and torque combination.
Our training on these is virtually all sprint efforts, so we're good-to-go in that respect.
- Sprinters love the fact that the resistance unit is so strong and the fork stand is so steady. I haven't seen a modern mag trainer that can provide nearly as much resistance. I'm talking: It can handle over 2,000w. Most other commercial fluid or mag trainers can't handle much over 1,000w.
Yes, if Sir Chris Hoy can't break one, I'm not sure anybody can 
- You can engage track nuts without using the plastic inserts. I didn't have any on mine.
Yes!
I would't bother scavenging parts from other machines to make a 100% perfect machine. If the resistance unit works and the copper disk isn't warped, it's useful.
Duly noted!