I wouldn't go so far as to say don't do it. Just be very careful. I've done lots of restorations on MG's and old Porsches. Even had an old 630 CSi once that I rebuilt the manual transmission on. The e23 is a very complicated machine with lots of parts that wear out. You didn't say if you already owned the car or are just considering one. I wouldn't plan restoring one of these if you expect to get your money back. I bought my '86 for only $1500 and it needed the brakes redone, the dreaded face vent not working problem, the broken driver's door lock, etc. It also still needs a paint job. My advice is read a couple of months of the board. If you can do your own work and want to use the car as a hobby, go for it. If you haven't done much restoration work before go with something simpler, like a 320i or something domestic. I have often had second thoughts about mine. It will be a great car when I am finished and I'll only have $2500 in it if I'm lucky. I'll also have 150 hours of my own labor in it though. Hope this helps.