You want to shift at peak HP.
Going too high on the power curve is as bad as going too low, it's just easier to recover.
My motorcycle's rev limiter is at 5500, but if I shift above 5200, there is a VERY noticeable loss of pull before the limiter hits.
If you hit the limiter, you've already lost the race if the other guy knows how to drive.
Not exactly. Many times, it's a better idea to shift higher than your peak HP RPM because the next gear will fall right into the power band, giving you an advantage in the next gear up. That all depends, however, on how badly your HP/TQ drops off after the peak. If it's not too bad a cliff, I'd keep going and then shift throwing you right into the powerband on the next gear.