Am I better off with one ppi pcx1500 or 2 pcx2125 amp to push two alpine type Rs , wondering if 2 requires more batts/power as opposed to just the 1 by itself
I'm not sure what the ouput is on those two amps but your power requirements will be determined by total output power. If the two amps are equal to output as the single amp the only additional concerns will be distrobution block, fuses wiring.
You're always better off limiting the number of electronics in a car audio system. As far back as I can remember, PPI was the best at playing the impedence game allowing some amp to be dropped to 1/4ohm!!! I would wire the subs to 1 amp and make sure the load will bring the most out of that amp.