Free your intake!!
-Buy a $20 high flow cone cotton filter from Amazon. Increased acceleration, increased fuel economy, sounds sweet.
Cut weight!!
-Take the metal rocker panels off the sides of your RAV4. Increased clearance by a bit, cut weight of vehicle by about 15lb.
-Take off the stock muffler. Shortened exhaust=less back pressure=more power. (You can use a $3 muffler hanger and a strong bolt to hold it tight.) Cuts weight of vehicle by about 25lb.
-Take off the spare. I only actually did this because my spare has a flat and I took it off the repair it. Even though, the cut of weight has made a difference in feel.
-Take out one backseat. Even with one seat gone, you can still squeeze two people on the one that is there. Effectively making your 5 seater into a 4 seater. Increased cargo room, cut weight by about 20lb.
Yes, the 89 Celica intake manifold will fit on the stock engine, though I suggest you do the full motor swap as it will be a massive upgrade.
If for some reason you cant afford that, then the above recommendations are excellent. What I did with mine was remove all of the seats, and installed two super light Recaro racing seats out of a Lancer EVO which dropped the curb weight substantially. I would guess it's probably an 80lbs savings.
Another way to reduce weight is to remove the windows. I installed nets on the windows which is a major weight reduction. Removed the window regulators as well now that the windows have been removed.
I plan on removing the rear bumper and designing a lighter, carbon fiber bumper that will accommodate my "modified rear end".
When I upgraded engines, I removed the power steering unit, and a/c unit out of my Rav which reduced quite a bit of weight as well.
