I don't recall exactly. But pretty sure they were < $200 for the pair. Quite reasonable for HAT.
Also... Audible Physics makes a kick ass 2" but I couldn't find the link for it. About the same price as the HAT
https://www.madisoundspeakerstore.com/approx-2-fullrange/scanspeak-discovery-5f/8422t-01-2-full-range/
https://hybrid-audio.com/speakers/unity/u2/
I'm just guessing at the size. But either of those would be tits. I own both.
BMW batts are beefy AF. They can certainly handle an extra 250w or so. You will be fine.
I would get the little mono and not have to worry about bridging the 4 channel.
The only ratio you should concern yourself with it the frequency response. Not a random front stage to substage power ratio. Besides... subs need way more power than fronts to be in balance anyway. How much power that is varies from app to app.
Get the subs that you want in there with a bass...
How's forum life treating y'all? I miss it.
In case y'all wondering what I've been up to, Skip01 and I started a podcast. Hopefully you guys will check it out.
https://www.youtube.com/channel/UCWfYEluq2Q6ieBwEKWk_jpQ