i dont think them being agm has anything to do with the voltage they can handle. there are 16v agm batteries. mine are 12v batteries, and 14.4 would be the normal charge for them. i know when i would start my truck on a really cold morning, i would show low to mid 15s before i had the mla module, the other day when it was 20 or 25 degrees i was showing 15.8/9 with the mla installed. normally, its at 15-15.5 when the weather is more reasonable. i know there are a lot of people running mla modules at 15.3 with 12v batteries with no issues, so i'm not worried about it.
you can't regulate the voltage, but you can order it to be a custom voltage. i like it, but its not a fix for voltage drops or anything. i was dropping to mid 12s before when i'd clip the amp, and still do. i have my gain set just past where the AC voltage starts jumping quickly and my DC voltage starts dropping, which is where i imagine the amp starts clipping. with most music, and my head unit at 55/62, i turn the remote gain knob up to about 3/4 to get full, clean output. i'll hold at low-mid 14s there while driving, if i take it much further it will rapidly go to mid-high 12s, depending on the type of music, duration of bass notes, frequency, etc. so it doesnt magically give your batteries more reserve power or anything, it just raises the charging voltage a hair. for the price ($170) honestly, i probably would have skipped it and put that cash towards a third d3100, since i'll probably have to remove one of the rear seats and build a battery rack anyway, but oh well.
