I know that after a certain amount of RPM's you need to get a billet flywheel. I also know that you also need a connecting rod. I usually see people commenting to get a billet flywheel if one is to heavily modify an engine. I don't usually see recommendations for connecting rods. So I am wondering at what RPM range should one go about getting a billet connecting rod. I plan to do modifications but want to know all the safety precautions beforehand.