It really depends on what you want. My friend has a MT2 18SS and in stock form, don't know the ratio off the top of my head, he found it was geared too much for top end. He dropped a tooth or too on the CB and it gave great acceleration, but a little less top end speed. I have driven the truck and I find that even with the smaller CB it is still very fast in the top end. Just follow what retarded pilot said to make a choice. Does it seem slow at full speed? If so go up a tooth on the CB. Does it seem slow on take off? Drop a tooth on the CB.