[jdmccright]

In general, I have heard it both ways...some say it helps, others say it doesn't.

IMO, if set up correctly, it should help performance of the engine and the A/C at least a little. The engine is not using power to turn the heavy fan and clutch. And when the A/C is running, the electric fan(s) should turn on as well to help cool the condenser (this may require a splice into the A/C clutch circuit). Finally, some fans can be adjusted to turn on at a different temperature than the thermostat (or the thermostat can be replaced with a lower temperature version allowing a slight performance gain), allowing a moving vehicle to naturally cool the coolant and lessening the electrical load.

Some will report that the reduced rotational mass will result in a feeling that the engine revs freer or feels peppier and slight performance improvement. The caveats are that they are sort of expensive for a good setup ($300 to $500) and rarely worth the power gained (3-6 HP), and sometimes require the altenator to be replaced with a heavy duty version to cope with the higher electrical draw.

If you are considering doing this and are not mechanically/electrically inclined, then pay to have it done. Hope this helps!