ummm, first of all cx is not wired for v-tech, if u go for a swap ur gunna have to wire it and thats not easy to do, second of all the vx and cx would both require rear mound swaps because the stock mounds on them will not support a b series motor, again this will cost more money and will be harder to do. The si on the other hand is already wired for v-tech, and b series motors are drop ins, meaning no additional work is required for the swap. yea the vx and cx are lighter but by about 200 pounds which really doens't make much of a difference, and your wasteing more time and money swaping in a cx or vx