I had this done to my 1959 BE35 K model. None of the components were in my plane to start. I purchased the parts through a fantastic source - our own Dr. Kevin H. The parts came out of a wreak. I had to clean the parts up before installation. The work was performed by a good shop in Maryland (one that has sponsored ABS Service Clinics) in Hagerstown. Tracey Potter runs the operation. We used new, custom made plumbing. Because we used Beechcraft original parts and installed everything just like Beechcraft did, and because this shop is a repair station (Hagerstown Aircraft Services www.hgair.com
), the paperwork was quite reasonable. This work was done about 10 years ago and everything works perfectly today, no maintenance issues ever. I forget the number of hours to do this work, but it was not in the 120 hours realm IIRC, my memory is more like 40 hours. By the way, there was no penetrations of the firewall on this job that I can remember.
I hope this helps you,