Funny you mention about the deck plate mod. I got the same concept from the Tacoma forums (CustomTacos.com) when first researching CAIs for the RAV.
The only problem which prevented me from doing something similar, is that there was no adequate space on the RAVs factory air box to mount a deck plate. You could use a speaker port tube, but then the problem would be accessibility for the 3" hose. You will find that underneath access (as you have pictured) is hindered because the air box rests on the RAVs frame/subframe. A side exiting port is possible, but would require a 90 degree bend and creative routing of the hose. :?
After weighing all of these issues, I decided to just build one from scratch. I relocated the coolant reserve bottle to gain more space for the CAI. Also, you will notice that with the removal of the factory air box, there is plenty of space to be creative.
