Has anyone here ever ran a cold air intake on their 4 cylinder 2.2.
I was just wondering how much they improve the performance ?
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Quick answer: Zero improvement.

At least on my '94.
Already has factory stock cold air intake.
There is an intake duct in the front bumper fascia that receives
outside ("cold") air pressurized by the car's forward movement.
Directly behind this duct is a plastic plenum behind the front wheel
that incorporates a "resonator" to reduce noise, and directs the air
flow to an opening next to the battery (so the battery case is also
cooled - nice since heat is not helpful for battery life - yet the
battery case also directs the air flow rearward).
Immediately behind the (fairly large) opening in the sheet metal behind
the front head light is a "snout" that picks up the outside "cold" air
and draws it into the air filter enclosure where there is an intake air
temperature sensor sending signals to the ECM to maximize efficient
fuel delivery to the injectors.
Here's something else (that could be disturbed if the existing intake
plumbing were altered). After the intake manifold "collector" (to
buffer air pulsation) there are long individual runners to each intake
port to utilize "inertial supercharging effect" - although with the
Camry's "fuel efficient" "FE" head (narrow valve angle) the additional
torque is delivered at mid range rather than high end.