Looking to improve gas milage...

I had read on MANY sites that by installing a CAI you can improve gas milage. Is this the same for all cars or is it more or less for smaller engines? I have an 98 Olds Aurora and the gas milage is adequate, but could always be better with the rising prices of gas.
So, here in is where the question lies? By installing this, Theoretically, should I get better gas milage or would it be a waste of money? Thanks guys!

Probably won't make much difference in economy. Given the same throttle position the ECM is going to see the colder, denser air via the IAT and MAF inputs, then to satisfy the O2 sensor and maintain the 14.7:1 Air/Fuel ratio the ECM will inject MORE gas(short term fuel trim). You might then make a little more power due to the higher air density and thus not apply as much throttle, perhaps this will increase OVERALL economy - perhaps it won't.

Your Aurora already has a factory cold air intake system. Aftermarket systems are primarily intended to increase airflow, not reduce inlet temperature......so you should not see any difference unless your stock airfilter is really dirty and restricted, ( or you drive around at wide open throttle all the time. )