Using a voltage regulator

Background: I live in Mexico. We suffer from a highly fluctuating voltage system. I have put voltage regulators on all sensitive electronic equipment (refrigerator, microwave, washer, dryer, computers, modems, routers, etc.) but use an S 15 APC surge protector on the stereo system.

Question: Since the APC a surge protector but NOT a voltage regulator would it be wise to put a voltage regulator between the wall outlet and the APC? Currently I have to set the high end of the APC to 135 volts to prevent it from constantly sounding the alarm and going to battery back-up.

We also suffer from brownouts which can be just as deadly to equipment.
Puerto - What specifically are you concerned about for your equipment? The APC S15 is, in a sense, performing a voltage regulation function because it isn't allowing voltages outside of a certain range to reach your equipment. It almost sounds like you're looking for something that will avoid "sounding the alarm" more than you're in need of better protection.

I'm almost thinking that a power regenerator might be what you're looking for, but not sure how they would perform under the power conditions you describe.
I guess what I am looking for is the ability to energize my equipment at a reasonable voltage level without having the APC constantly reverting to battery back-up. It wouldn't take long to run out of battery if the monos, et al were in full swing. As it is, the system is operating on about 130-135 volts most of the time. I think that is too high. I don't mind the alarm per se, glad to have it but prefer that the voltage remain steady throughout at 110V. That is what has prompted my question about the feasibility of installing a voltage regulator between the wall outlet and the APC. I'm just not knowledgeable enough to know if that would be a harmful set-up in any way.
Mceljo: What you have is what I need. That is exactly how my other regulators work on the computers, etc. Going back to my original thought - if a voltage regulator reduced the high voltage spikes back to 110V BEFORE sending the power on to the APC would this in some way be harmful to the APC or SQ?
I can't imagine how. It might limit current and that can have a negative effect on sound quality, but it won't damage anything.