I just got 900 ACE 2014 with 26hrs on it last week. The steering and wire series had been done in the 1st maintenance as part of recall duties. Engine hatch was not faulty with this serial number. Running great after 4 hrs of testing.
Why old instead of new: came with manual reverse and got it about 800€ cheaper than new, one year of warranty remaining as two years has been the standard in Europe. So if it's a lemon it'd be seen by now. Second hand market of PWCs is very good in Finland - very little offering of new and more economic PWCs. Easy to get rid off if need to - a used one can be sold without any money loss.
I put the flushing kit just as the different forum threads suggested, one things i would emphasize - do not make any valve in the flushing kit itself. Rather have the valve in the garden hose, otherwise you will someday forget to open the valve for riding. Currently just fixed it with a strip wire, when I have time to remove the manual reverse out of the way will fix it permanently.
Other on-going mods:
- GPS installation: I have an old Garmin nuvi 500 from a boat with a naval map in it. Very old kit but actually great for a jetski, water tight and very few buttons.
- 12V power socket: I just put a socket in the bottom of the "glove compartment", just using a standard circular marine socket there
- Running light and pilge pump installation under planning: will install the switches first inside the glove compartment, white running light required after the sun set in here (well, sun set is around 11pm this time a year, but it's lit enough to see until 1am

. I will probably glue the pilge pump instead of using screws.
- the 1st aid kit compartment hatch and the opposite hatch revealed good space and a route for electrical cabling inside the chassis, should be no problems there - just need to think whether to leave the wiring connectors inside the chassis or the 1st aid kit compartment to allow easy removal of upper deck.