From Stefan 4/5/13.
We are one minor version number behind with some of the documention. For technically inclined builders this should not be a problem. It will probably be another month until we have the latest CAD model up and updated the build instruction. The BOM is current and we have photo documentation of the latest build here:
We have about 100 machines out there, 400 people on the mailing list, about 20-30 actively participating in the discussions and answering questions. Most people built their Lasersaur from the instructions in the manual with a couple of interactions on the mailing list.
The mailing list is the place to solicit help. There may even be people on there who are willing to come out and do the build with you on site.
I think there are two or three systems with a 150W laser but not 200W, afaik. Both upgrades require and extension on the rear right side to house the laser tube. They also need the 5000 series chiller instead of the 3000. No other changes should be necessary.
Metal cutting is tricky and requires very controlled conditions. Somebody on the list claimed to be able to cut thin sheet metal with the 150W tube, oxygen assist, and a 50mm focal lens. Personally I think your best bet at cutting metal is using a synrad pulstar 100 laser instead of the china tubes. This laser pulses at 300W and reportable can cut 2-3mm of steel. For 18k it's the cheapest option in the RF laser field, short of tracking down a suitable used laser. The pulstar 100 fits into the Lasersaur and requires only minor changes to the controls/firmware (from what I could gather reading the manual).
Upcoming changes are also typically posted here: http://labs.nortd.com/lasersaur/manual/revisions