That person is an idiot, stop listening to him.
So you like loud and peaky and something that is much less loud and flat response at the same time. Or perhaps you just don't understand either of the opposites.
You can but it makes no sense and won't help you at all. Back to liking the FR thing....obviously you don't.
He has A LOT to learn.
Seriously, just run one amp. You never once referenced a meter in your posts so chasing less than audible sound differences is pointless. You have to double the power to hear a difference. Running a second amp won't do that for you as between reaching the thermal & mechanical limits of the driver and power compression will stop that cold in its tracks. The 2nd amp is a waste of money, don't buy it, don't use it and don't invest in the necessary electrical to add it as what you propose is literally akin to flushing money down the toilet. I would also be vary wary of any other advice said friend is giving you as obviously he is a complete noob and infatuated with all of the wrong aspects of audio. Headroom is important, but this is a sub that is going to play the very smallest of regions in the audio spectrum where your ear is super inefficient at hearing distortion or anomalies. Terrible place to spend extra money for no reason.
Put that budget you were about to waste to good use and spend it ALL on your front stage. It will make a monstrous difference.