Re: Italia (series 9s) vs. Espania (152s)
Have rebuilt/refurb'd both DGVs and DCOEs.
The older Italians (series 9s) used ball bearings on the shaft (check for play/slop). If there is slop.....good luck tuning to 100%. Spanish use a cartridge bearing.
Beware: there can be a few different older DCOE series out there. Know what you are looking for (series 9), other series runs can cause headaches, frustration and become useless but charming expensive paperweights.
If you can even 'find' 3x old italian (series 9s...hoarded today?), you are likely entering a competitive hunt and bid war against those that 'have' to have them too (Alfa, Jag, Ferrari, Lambo, Maser, Aston Martin folks etc) for their high dollar concourse resto. Spanish 152s are brand new, clean, on the shelf now, likely have a warranty, Tech support, are basically ready to go!
Plan on rebuilding/rejetting/cleaning everything on an older set of Italians from the get go, then install and dyno tune and hope the old girls are solid (most like are).
New DCOEs you open the box, inspect (tweak if ya like), install, hit the dyno then the road or track. Done. Huge time, $$, and drama savers.
My two cents: if you are going drive/use it go with known entity and source. If you are building a museum pc that will see little use: happy hunting and prepare to cross swords.
hth