I'm in the resto/repair & while I'm in there phase, so won't even answer - too much $$$$'s!!!!
... but that's the disease.
As for DD use, my test always was & is - if it takes me more hours to do it at my rate of pay (including: parts, set-up, disposal, f-ing around to figure stuff out, re-doing what I may mess up, etc.), vs. the charge to have it done right by a
good pro - if the latter is equal or less, then I let them mess with it!!!!
Another factor to consider is if the pro/shop has a warranty on the work if it goes bad &/or if any parts warranties are less or eliminated by a DIYer, then you have to factor that into it.
Sometimes it's just whether you have the spare time & inclination to do something, vs. just having it done & enjoy the
or
!
Right now, some things which I feel I may not get perfect on the resto, &/or I want my long time factory trained 914 mechanic to get right before he retires, then I'll go to a pro. He's seen so many 914s over the years & learned so many tricks, that he can get straight to the real cause right away, rather than some of us lesser beings taking hours to eliminate everything else!
Others are right though - the basic 914 regular maintenance stuff is pretty straightforward, even a simple tune-up & valve adjustment - assuming the d-jet EFI is running right & sorted-out with no defective parts to track down - any of that is a couple of hours to 1/2 day to get right - including getting the grease off your hands!