I don't own an Xpress boat, but I have a G3. Mine is the HP180, with a Yamaha 150 HP outboard.
I get 53+ MPH out of mine with a manual jackplate. I haven't spent a lot of time making precise adjustments to my jackpplate, so I don't know if I have it setup optimally. But I do know that I'm glad I opted for the 150 HP since that's what my boat is rated for.
I also think my prop is pitched incorrectly, at 19. I think a 21 would be much better for top end without losing holeshot, but I don't want to spend $600 just to find out.
An X19 with a 200 is probably a 60+ MPH boat. If you're not worried about being the fastest, go with the 150 HP and save some cash. But keep in mind that if you add two Talons or Power Poles to the boat you may want that 200 HP to compensate for the weight of those hanging off your transom. Just some food for thought.