hi,
this site came up not to long ago and gives you everything you need to know about the 5513 sub history, everything from m first, feet first, pre comex, comex, and 5 different maxi dials.
http://www.5513mattedial.com/
Thats a hard one. Regarding subs: If you spend a bit more and buy a 1680 or 5513, these will likely hold value more. At the price point you are looking at you may be able to get a newer sub, 1990s on, but I doubt with box and papers. An older model will cost more but likely increase in value...
Hi,
I have heard Lervik is a good place and has experience with vintage.
Lervik Ur
Otherwise, Arcticboy on this forum is a watchmaker in Oslo. He may have experience with that movement and I bought a Speedmaster from him which he serviced and runs at about 1 second off a day.