in the back to back dyno tests (trying to extract the best #'s) that were performed on my VE equipped car, a short ram (with bellmouth and NO filter) produced NO benefit over a hotshot cai (with jwt pop charger) . this was ~4+ yrs ago when a local sr20 turbo freak ; and i were testing different header and/or cam designs (i don't remember which).
i've tried running short ram on the street a few different times, and my calibrated
butt dyno agrees. best performance for my particular setup is WITH the cai installed. fyi, i've gone away from the oiled K&N filter and gone with the AEM dryflow. not really for any power gain, i just "think" it filters better. ymmv
once my VE build is finished i want to protect it with the BEST filter on the market, regardless of a couple hp + or - .