Using end points to reduce power to motor

[Verde]

What are the pros/cons of using a motor that is too powerful for a particular track, but is limited to say 60/70/80% of it's potential by adjusting the end points on your tx?

Im coming from a local club perspective where affordable competitive fun is more important than sticking to hard and fast brca rules. I don't mean extremes either, more like a 10.5 with end point reduced down to save buying a new 13.5 or 17.5t.

Many thanks.