99' Ultra 150! I'm not sure about the other model years because the 99's were hitting 70 plus and the coast guard got on Kawasaki about the stock speed so it is possible other model years were slowed down a bit. For new ski's, look at the Ultra 260X or the Yamaha 1800 2 or 3 seater. The model number on both escapes me at the moment but it is something like the FZS or something like that?
My 99' Ultra has been clocked faster than 73 at it is stock. The Yamaha GP 1300's are very fast but I have raced them and beat them. With the Sea Don'ts, I have never raced one but I have heard that they too, are very quick. It's just that I will never own one because I love reliability and know how Sea Doo treats customers with problems.
None of the boats mentioned in this post will do over 70 mph except the sea zoo. The sea doo rxpx would smoke any stock gpr or ultra. Gps speed readings mean something. The speedometer on boats is highly unreliable. Both boats are fast but the rxpx would run away from them. I believe it hits 50 mph in like 2.5 seconds.
there is the hsr-benelli series r race edition which they say runs up to 90 mph. they are sold in europe so they might be kind of hard to find and cost about $25,000-30,000. u might not want this because of the price, but i was just answering your question