Part 103 does not demand low power and high drag. It does have weight and speed restrictions. You could have a slippery 1000hp monster as long as it stalls power off below 24kts, maxes out at 55kts and is below 254lb. A airspeed sensitive governer is an acceptable alternative to massive drag with a powerful motor. My appendix permitted power will be around 15hp. It'll have around 40hp and a governer. Great climb, slippery, decent range but still legal. i haven't looked to see if it will pul a loop, I'm just trying to make it plenty of fun.