CPU limits on Tiers worked pretty well. You had one limit for all bots. So let's say you build a max cpu bot out of t1 cubes and guns etc, then you had a big bot, but because of the tiered parts, you were t1. If you build the same bot again, out of t10 parts, then you had a max cpu t10 bot. Not sure if it worked exactly like that though. It worked atleast.