1. I do not have speedometer atm, but in a few days i will get it.
Aside "fastest" vehicles, always keep in mind that there are a lot of bugs for different vehicles, and some of them can give you some "speed bonuses". Like this one.
2. I am just wondering if it is possible in HYDRA to move forward, then do a maneuver, so you will fly AT THE SAME direction, this maneuver will not be "symmetrical" (in your tutorial you are showing "symmetrical" maneuver when you are going UP to perpendicular position) and you do not need to go UP, you just switching from forward flight to hovering and back to forward flight.