Well I just went through all the set up pages, don't see the people talking about the bravo4 there... but I definitely have been told several times how it is the ticket, but read people may need to take the cowl off and have someone step on the pedal to the floor to insure it is opening all the way up. I'd start here, it's free
the older z8's were faster and suposibly merc took some hp out in 2012 or something.