bro you do not want to argue with orion about toyotas
and on a side note, NO you won't see much of a difference or horsepower gains. the only other way i would imagine you'd see much gains is if you
modify/get a bigger throttle body
bigger intake manifold
at least 3 inch piping on CAI
and spend decent money and get a K&N filter
thats the only way i can see much gains on a cai, and that comes from experience on helping my cousin with his b18c1 swapped civic si hatch. he did all that i listed there PLUS full catback with 3 INCH piping straight to the back and only gained around 12 hp. alot of people mistake alot of the principles of how engines work, including me. when i first "got into cars" i was thinking small. CAI, putting a "aftermarket" muffler on stock pipes
thinking i was getting "speed" . until someone introduced me to the wonderful world of turboes. like orion said, if she wants REAL HP gains she might want to look into these:
cam gears
camshaft(don't know how that will work with the vvtl-i)
aftermarket throttle body
full exhaust(and i mean full, not just headers and a tailpipe)
piggyback ecu system greddy emanage is pretty good for decent tuning(again i don't know how this will help or hurt the vvtl-i)
lighter flywheel, pulleys
i don't know how much HP that will get you, but its way more practical than sticking a whole bunch of rice mods on a nice car.