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.
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.
OK! The verdict is in! I hooked up one of my voltage regulators in between the wall and the APC. According to the APC it is putting out a steady 118-119V to the APC. SQ you ask? Can't tell the difference. My peace of mind? Much better.

I have left the APC alarm setting at 134V as a "just in case".

Thanks for your input.
One last thought for those that are wondering - the monoblock amps are NOT running through the APC (hence the voltage regulator). I think they can handle the higher voltages - to a point.

Any further thoughts are welcome.