I just recently bought my '00 SD Challenger 2000 w/ the 2.5L, v6, 240efi, M2 SportJet... for just slightly less than your price. But my engine was not running at time of sale and had a disclosed higher reving problem. I did ensure mine had good compression in all 6 cylinders before buying.
The 20ft Challenger is a nice sized boat. A good running 240efi will move the boat upwards of 50mph at around 6k rpms in good running condition. That's pretty fast. The boat handles like a giant jet ski... with jet ski like steering. The boat is also lighter than most other 20ft bowriders and such... which has its pro's and con's. Easier to tow... more slappy in the chop. Plus the jet drive takes some practice in docking/slow-speed maneuvering.
Down sides are finding mechanics to work on it. Sea Doo won't work on it, since it's a Mercury powerplant. It's essentially a Mercury 200efi outboard powerhead in the hull... mated to the Mercury M2 jet-drive. A good 2-stroke Mercury mechanic should know their way around the engine. Otherwise, if you wrench yourself... parts are still available... although some items are getting more rare (good blocks/cranks) and expensive (TPS sensors).
Cheers!