Probably not worth the money and effort to install on a 92.
At minimum, you'd need the speedo gauge and wiring, the paddle wheel sensor/pickup for the rear of the boat, and (I'm not entirely sure about this) wiring or programming of the MPEM.
In theory you could use a pitot tube style speedo found on most full size boats.....just don't know if the gauges used with these would fit normal Seadoo locations on the bars/hood.