Thanks for all your helpful replies!
Basically, I'm building some models (Kitbash replicas of the DS9 Frankenstein fleet), and there's some cutting that is a little more involved than just using a knife or hand saw. Specifically, I'm currently building the U.S.S. Yeager, and it turns out that it's a bit more complicated than just gluing the Voyager saucer top onto the Maquis Raider. Apparently the underside of the saucer (where Voyager's secondary hull would have been glued) was cut out a bit so the top of the Maquis raider actually goes inside the saucer. The plastic is big and pretty much impossible to cut with my hand saw in vaguely the shape of the raider.
Anyway, here's what I found on Amazon:
This model (the 4000-6/50...whatever those numbers mean) is a plug-in, variable speed model with lots of accessories, plus the flex shaft attachment. Would this be a good buy for what I need?
Also, there's a workstation to plug the tool into so it's easier to use the flex shaft attachment while it holds the main tool in place. Is it worth getting too, or just an unnecessary extra?