Probably an extravagant claim.

Without supporting modifications -- probably no increase at all!

Will probably be the same or a slight decrease.

Lots of people do.  And the noises helps convince them that there are
power or gas mileage increase when, in fact, there are not.

I thought that for decades the U.S. government has required car makers
to state HP at the wheels because previously car makers gave inflated
numbers.  What's the weight of your car in kilograms divided by the
0-66 acceleration time in seconds?  That's supposed to give the net HP.
Also did you have the hesitation fix installed?  In FWD Corollas it
consists of adding a restrictor to one of the EGR vacuum ports,
changing the accelerator pump lever and a couple of jets, and raising
the float level to the top of the gap in the window.

Will a Weber 32-36 give much of an improvement?  Because the Aisin for
my 4-AC engine is 30-34 (I don't know if that's the proper measurement
-- I took a ruler to one of the carb gaskets).  Also how can a
performance carburetor give equal drivability if most of the vacuum
controls, the oxygen sensor control, and the primary barrel cut-off
solenoid are disconnected, unless you run a richer mixture, which may
not be good for fuel economy?

I think that my 0-60 time worsened by 3-4 seconds when the A/C
compressor ran.  :(

J.C. Whitney may still sell an adjustable  vacuum-operated switch for
this purpose, but I used a mechanical switch hooked up to the throttle
pedal lever because then I could keep everything inside the passenger
compartment, away from the weather.  If you use a vacuum switch or have
a manual transmission, you'll have to add something to keep the A/C
clutch disengaged for at least 1-2 seconds each time the switch is
triggered, or else the clutch will chatter each time the transmission
shifts.  For the vacuum switch a time delay can be made from a vacuum
chamber, check valve, and air bleed (bypasses the check valve and sets
the amount of time delay), or you can have the switch control a time
delay relay, which will also work with the mechanical switch.  However
I had problems finding time delay relays that weren't expensive or that
worked on 12V (almost all needed 24V), so I simply built a time delay
and had it control a relay.  I chose a normally closed relay so its
coil was energized only when I wanted the A/C clutch turned off,
thinking this would put less wear on the circuitry (I'm in Arizona,
where car interiors can reach 160F).  I also wired a toggle switch to
bypass the relay in case something failed.  If you use a mechanical
switch on the throttle pedal linkage, mount it on the top or side so it
doesn't interfere with pedal travel.  I used a microswitch with a long
lever and mounted it on the side of the lever.

It may be practical to use the existing throttle position switch,
especially if you have the 3-4 position type or a throttle position
sensor, but be careful to buffer its output to avoid loading it down
and screwing up the computer.