I am new here although I have been a lurker for a while.
I have a Durst L138S and it is every bit the amazing machine as everyone has said. I read in an old issue of Camera & Darkroom where Joe Englander said that the condensers of Leica and Durst enlargers were special because they were made of out optical quality 'water-white' glass unlike the Coke bottle glass of Omega and Beseler which was gave condensers a bad rap in the US. As they were too expensive for many amateurs then, not too many amateurs had access to them.
Pristine Latico condensers can often be found on ebay for about $25.00 to $49.00 each. Sometimes, used enlarger dealers enter the auction and then prices may go crazy for certain focal lengths like the Latico 200. If you're patient, you should be able to find something eventually. The ones marked Latico xxxT are coated condensers meant for point-light sources; these are exceedingly rare and fetch a premium naturally. Last week or so, someone paid over $2000.00 for a Durst L138 with a complete set of seven Latico xxxT condensers. The ones marked Latico xxxR are reducing condensers.
When you disassemble the L138, please be careful that you do not release the head counterbalancing spring accidentally. I did and it nearly took a huge chunk of flesh out of me! The top column shot out from under the head and grazed my lower leg. It shaved off the skin and left a huge bloody patch where it bounced off the bone. It is that strong and it was painful as hell. If it had hit me square on, it may have severed an artery and I would be dead for sure. So, please be careful dealing with it.
I found most of the parts I needed off ebay. I had to be very patient. If you are enlarging 35mm frames, you need the special recessed lens mounting tube called either the Seimar or the Latub. Perhaps both work on the L138.
How do you convert it to work with tungsten-halogen bulbs? Would anyone care to tell?