Can a vehicle have too much horsepower?

Only in a manor of speaking, yes. The only time(s) I feel there is to much HP is when ;

The suspension can not handle the power.
The body twists up and stay bent.
When the driver is scared
The throttle is super touchy/difficult to control. Which also makes a good case for the rest of the drivetrains set up/combination. Super high stall loose converter/ gear ratio.

400 hp in even in a light weight Scamp is not a lot. The manual transmission adds something in a possible lack of control combined with a higher gear ratio and tire size. As in height or diameter. At 10.5 wide, that should hold the road pretty good unless your clutch dumping at high rpm. Next item up for inspection would be rear springs.

It is a cumulative thing. It just engine power. Like a math equation, the more plus signs you add up due to equipment not being up to par or farther away from stock adds up. Add up those things. The more things you add up, the worse it gets.

My 5.7 HEMI RAM can over power the tires and/or suspension at some point in the throttles travel.