Buy nothing without taking it out on the water for a test drive.
Some models are tempermental with fuel pressures and other things. They might run fine on the trailer but not in the water.
I have a 2002 Seadoo since new, last year it would run at home on the hose but not at the lake. The fuel pump was working but not putting out the necessary 100+PSI. It is $1100.00 dealer replacement. $700.00 out the door if you want to do the work.