As a competitor, it’s excellent. I know I’m not being beat by $$$ on the track. There are other amateur series where there are all kinds of loopholes and with the right amount of money, you can get a special-built engine within the letter of the rules that is unbeatable unless you have one too (I know of one guy that paid $40k for a “special” LS1 engine). My engine is a stock 110,000 miler and makes the power I need for the series so it’s all good.
If you go here:
http://www.nasaproracing.com/rules.html
and check the rules sets for Camaro-Mustang Challenge, American Iron, and Super Touring you will see the dyno procedures in the rules. I know that other series have these rules, too, but I have never looked to see who else has to run within power limits.