I agree with k-star and camaroman. For most engine builds short of professional circle track or drag racing, rod length is a small issue in a total engine build. I would look at the whole picture. If an engine combination came with only one choice of rod length, your choice is made. If more than one rod length is available, use the cheaper one and use the left over money for something that will make a tangible difference. If the price is the same, flip a coin.