BC I'm planning on using 4 So you have a budget of $800 total for amps for your subs, and want the most power you can get? Do you have an additional budget to upgrade your electrical? Doesn't make much sense to drop $800 for a bunch of amps if your electrical isn't up to par, and I highly doubt replacing the battery with an AGM is going to be enough. I'm not trying to be rude but if you would read I will upgrade electrical That is not included in budget as I was always planning on it and just dont see the use in rerplacing a functional battery that has not faultered a bit with what i am running currently. I am already running 3 amps on it i plan on changing them all out to a better line possably same manufacturer. If you would have read you would notice that my current budgetis non existent so I am simply trying to get a broader range of ideas. In the past I've done big high quality comp builds going back to 96 wit RF Punch Power DVC 4-12's off 2 Punch Power 50M's on stock electrical wihout issues so Ill address alt if needed I plan on Battery upgrades that is not included in the amp budget. I do not have a hard limit im simply trying to see what I can getr away with. I read that you mentioned upgrading the battery, nothing more. I apologize for not catching the inference for further electrical upgrades. Other than Big 3 and Battery what do you suggest. I'm just curious what your recomendations are. Do you have a degree or masters liscense in Eletrical fields. I do I have done some calculations already so please enlighten me but I doubt your expertise isnt close to my background in this field. But please I want to hear your suggestion Unfortunately I do not have a degree in EE, so please feel free to take anything I say with a grain of salt. I've heard fast food is bad for health, but I'm not a doctor either! Anyhow let me speculate, and correct me when I'm wrong. You have four sundown X's rated for 1250watts each, so optimally you'd like 5000watts total for your subs since that's what they're rated for? With zero change in impedance, and 100% efficiency from the amp(s) that would require 5000w/14.4v=347amperes Say I'm being over optimistic, and you'd be happy with 2500watts, 2500w/14.4v=174amperes From what I could gather(which may be incorrect), the 07 mini coopers have an alternator rated for 105amperes, and it's not common for manufacturer's to use larger than necessary alternators as it's not cost effective and doesn't help with the HP and mpg. So I would presume that upwards of 80-90% of what the alternator is rated for is what the stock electrical demands, but let's say it only uses half, so 105a/2=50amperes. So you have 50amperes from the alternator, and say you have a big AGM battery like the xs power 5100 with an AH rating of 60, so for one hour it can discharge 60amperes at 12v? Let's pretend it could do that at 14v though. So for one hour you have ~110amps. 110amps is a lot less than 170amps or 350amps, so much so that voltage would quickly drop below 12v, you would risk ruining all electronics, and ultimately end up with a dead battery. Back to reality, the alt doesn't have a 50% excess in amperage, your amps aren't anywhere near 100% efficient, impedance on the amps aren't constant, and I didn't account for any amps you may be using for the front stage. So my suggestion would be getting a high output alternator if you plan on running anywhere near my speculated figures of power. I originally asked why you wanted to use two amplifiers, when one amplifier alone could easily surpass your vehicle's electrical. If your original post was clearer than perhaps I wouldn't have "ragged" on you about trying to use so much power with little change to the electrical system. I know if I were in your shoes I would most likely opt for a smaller amplifier that doesn't require all these costly upgrades as the amount spent and the gain in output wouldn't be worth it to me, and especially considering all the cone area you have available. Though as you have pointed out I don't have any degree to support anything I've said, so feel free to disagree. and thats why volvos are the best ladies and gentleman!