Regardless of whether you could actually mow at top speed, three things that I notice: 1. They put a ROPS on it, but where's the seatbelt? 2. I didn't notice any suspension, either frame or seat. At 25mph and without a seatbelt, I think one would have a hard time staying on the thing. 3. It's difficult to tell how the deck is suspended from the frame, but I'd be willing to bet it wouldn't hold up for long consistently mowing flat out.