Horsepower is great, but the mark of a great engine is one that can put out fairly equal numbers. Horsepower doesn't tell the whole story. Horsepower, say boosted horsepower, will win a short race from a roll maybe but in road racing or from a stop where forward bite (torque) is needed, it has been proven to be the ticket time after time. But, you can't make torque without the horsepower.

Look at the Mustang for example, the GT has 260 horsepower (which isn't really that much) but it puts out 302 lb/ft of torque which is what makes it quick. There are bolt ons to increase the power, but increasing the torque numbers is how to make a strong car that can pass ANYWHERE, uphill or down.