um...i'm no expert, but i have a pop charger, and it doesn't sound quite as mean as a cai, but silversx hooked me up with a hell of a deal, it's his old one, and i saved about 150 dollars or more from getting a new cai. he said i'd get 6-8 more hp than before and i have noticed the difference. it sounds a little meaner, runs a little meaner, but cai's give you at least twice the hp if not three times.
and do you have a picture of your maxima?
Pop charger is a nice filter element, with a velocity stack, that is much more elegant than the filter on my hs intake. My pop is sitting in my basement. I should probably sell it, but I might switch intakes down the road you never know.
I wish I could have it on there with the stack and all. I heard the prcai can be set up with one. I would bet it would be good for a 1-2 hp esp up top.