I have this same boat - except this one is better because it has a better console arrangement and under deck tank.
Mine has a Yam 100 4 stoke and the boat tops at about 41mph. A 2 stroke 90 would most likely be quite a bit quicker. Someone I know has a 130 2 stoke and reckons he gets 60mph (or knots I can't remember) but I have no reason not to believe him.
This is a great boat, often compared to a V-Type (no, it's not a V-Type!). It's very light and has a very good balanced feel to it on the water. Deep V is a bit of an exageration IMO but it handles very well in all kinds of conditions. It IS good in a swell (and I've seen some serious swells) and it excels when there isn't. But it's not a 'lifeboat'.
I seriously love this boat and would buy another. I've owned a Humber and a Chinook and this is far better.
AND the hull has been used for racing (successfully) - ask cookie.
The hull IS narrow and it's one of those RIBs where you are feel like your sitting on top of the water rather than 'inside' a boat - more so than your average RIB. But these features combine to give it a very 'nimble', responsive feel. And it's easy to tow.
Weight - well it is seriously light. I've never weighed it but I tow it on an unbraked trailer. I reckon it's bordering on 750kg. I certainly never had a problem and drive hundreds of miles with it (sometimes loaded with holiday gear I must admit).
Remember that the boat is one of very few. (I love that). But you may have a problem selling. That's unfortunate bacause people are seriously missing out!
Take it out fro a trial and test (measure) the speed and handling for yourself.
I'll have mine at the RIB raid in Wales & anyone is welcome to have a go.
ps I have no connection with Olmec whatsoever and bought mine on the strength of a test drive.