before I got my camaro muffler, my short ram/wai was better for the mid-upper rpms. Then again, I left my stock plastic tubing in there (between the headlight and the stock box) so I suck up cold air in the higher rpms anyway.
after I got the muffler, there was a noticeable increase in torque in the whole range and an increase in lower-end power.
If all goes to plan, I should be able to tell you how things go with cams and a header later on this year.
in short, there is little-to-no difference in the performance between a short ram and a cai.