By SP-9 is definitely the original Mk I. I bought it new in 1988. When I did they had just introduced a new and nicer looking faceplate. I never updated the unit because ARC upgrades are just ridiculously priced. The Mk 1 version retailed for $1695. The MkII version was $1795, but the MkII upgrade cost something like $800. so I never bothered. I just always felt that the $800 would be better off spent elsewhere in the system.. If I ever came across a Mk III with the remote control I would probably jump on it for that feature alone, but they sold very few remote equipped units to they are very hard to find. I have only ever seen 1 listed for sale and I called the guy withing 15 minutes of the post going up and it was already gone. The original SP9 was and still is a great preamp, so outside of getting my hands on one with a remote I don't see myself ever upgrading it.