I've had an alumi-Kramer for 29 years. EXACT same body as that one as a matter of fact, though mine was a slightly earlier one with vol/tone/vol/tone knobs, (2) series/parallel switches, and the pickup selector. It also had the better neck attachment setup with (3) machine screws going into the spine of the aluminum part of the neck. I was way into Stanley Clarke, and at 18 could NOT afford an Alembic, so I went for the Kramer. GREAT tones with the original Schaller P/J pups. VERY convincing P Bass, Jazz, Ric, and Alembic sounds. I eventually had the frets removed and EMGs put on, and that's how it exists today. Sounds fantastic as a fretless, and the EMGs really work on this bass. Everything else I own is passive, but I'm leaving this as-is. As far as 8 strings - I had a very rare (1 of 1?) Kramer with the XL-9 body style. Quote from the Vintage Kramer web site - "The XL-12, a 12 string model and XL-98 8 string bass are still a mystery as not much information exists on these models. Presumably these had the type 2 body style." I sold it for $1100 a few years ago after I landed my beloved Ric 4003S/8.
Anyway, I like these instruments a lot. The big bummer for me is major neck dive. You get used to it. A grippy strap and wearing it fairly high helps. The Stagemaster on eBay is a good looking bass. I'd pay $800 easy if I were looking.