i say you could make the meanest ugliest crookedest cuts, as long as the motor runs better you've improved it. if it gets better gas mileage, has more power on a smoother powerband and lasts 10 gallons race tuned, you need to go in business with that. sometimes making "mistakes" at something reveals something none of us may have thought about. i don't have a dyno but when i mod a motor i wait until its about a gallon old and i race tune it and see how far it can jump and how fast it goes. then i mod it and race tune it again and see if it improved. i haven't done any timing mods yet, but i see marked improvement on all the motors i've modded. one time on my s3 the first time out its temps jumped up to the 350's, i thought i killed it with the mod but it was just the front bearing had been leaking, a common problem with the motor, the l2g's have better bearings now. on the crank, some mod companies remove or scallop the weighted end to balance the crank cause it is actually out of balance from the factory, not by much. when i scallop the crank shaft i like to go deep into the opening and have the whole scallop round out of the hole and towards the bottom of the weight. i've seen a lot of modders leave the internal edge sharp. modding is definitely fun, just be ready to make a mistake and kill a couple motors once in a while.