I've owned a few Ex-Factors back when they
were under $1k ($750-$800) but I wasn't a big '80s music advocate - I liked the Ex-Factor because of its design. And, I love the sound of a Kubicki pre - I can pick it out before I see the bass. (this actually happened once!) And it is his
pre that sounds like that - I have two Fender/Kubicki 9v pre's in two of my basses (a J and a T-bird) and both live and recorded - they both sound like a Kubicki. However, they don't have Phil's exceptional drop-D Ex-tention which makes a Kubicki Ex-Factor exceptional to this day. So to answer your question, I'm not familiar with the SB 1000 so I can't say how they are different, but I don't think an Ex-Factor
sounds '80s, unless it's slapped maybe. To me it sounds like a very distinctive bass, one that could be picked out in a blindfold test by those who have internalized that sound.
But I hear you, they are prohibitively priced now. When I bought my 1st Ex-Factor (a black '86) I called the Kubicki phone # (pre-internet, at least for me!... about '94) thinking I'd be talking to a rep. Phil himself answered and generously gave me a lot of info. (I knew very little about them then) In the conversation he asked how much I bought the '86 for, and I said $800. He said "I'd have paid that!"

As much as they are now going for over what they were new - if Phil was still alive I think he'd be happy that his basses are now going for such prices.
I'd like a birth year bass too... but a '53 P-bass is a bit out of my reach.