In case you didn't check, there should be an in-line fuse on the +12v wire for your aftermarket head unit. You might want to check it first.
As 2k5gtc said, I agree that the pop sound is unrelated to your new unit not working. It's most likely as he said; your remote voltage is +12vdc but your amps require 5vdc or some other odd voltage. This can be fixed by splicing a resistor in-line with the remote wire to your amps, which will bring the voltage down to the proper level.
You might want to do some reading on car stereo installation if you don't know much about it. It's easy to ruin things if you don't know what you're doing but once you learn the ways, you'll find that you can get a lot of free 12 packs by installing stereos for people.

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Black 2005 Mustang v6, 5 speed, IUP, EUP and Leather.
Razzi 1/4 window scoops, Mustang GT Sway Bars, Flowmaster American Thunder Single Exhaust, Clear Front Turn Signal Lenses, Demolet CAI, X-cal2 91 tune, Hurst Comp/Plus Shifter, FRPP T-Lock, Ford 3.73 gears