I finally watched The Keep recently and it was fantastic! Been searching for a bluray version since you mentioned it here and i found a spanish edition.
I also have the spanish edition, which is basic (no extras) but offers a very nice picture quality. As I'm a big fan of this film (and Mann's movies in general), I also own the very expensive but very classy australian 4K Blu-ray edition from Imprint...Master Ray, if you're reading this...!

:
https://viavision.com.au/shop/the-keep-1983-cross-replica-limited-edition-4k-uhd-2-disc-blu-ray-cd-imprint-collection-438/ By the way, I still haven't seen "Ferrari"! Last I heard, Mann is supposed to be shooting the sequel/prequel to "Heat" next year... I don't know if that's good news, but I'm still hoping for at least a good thriller.
Fun fact: a friend of mine is a friend of the manager of Tangerine Dream
Please ask your friend to beg Tangerine Dream's manager to release the complete soundtrack of THE KEEP on CD/vinyl!!! The soundtrack to THE KEEP has NEVER been officially released on CD/vinyl, because I suppose there were some issues between Tangerine Dream and their record label at the time. But it's very frustrating because it's my favorite soundtrack of theirs and I would love to own it on CD/vinyl!