Bushwalk Australia

That there is an Alpine subwoofer, I saw a 15" Boston Acoustics sub in a box on the side of the road last week, I was half tempted to grab it.

My mistake Yes it is an Alpine
Always stop to pick up if you can, especially name brands with big magnets as most drivers can be repaired cheaper than buying new. Car subs sound better in cars but I'll use this for a party then give it away to a mate who needs one for his shed

You should be able to find the T/S specs for that sub pretty easily, it will no doubt play quite low in that drum but it it will hit it's X-max well before it's rated power, that is if you are keeping the volume at 205L.

I've already done the simulations.
Rated power isn't what I normally design for, I usually aim for the lowest F10 I can get, SPL per watt is best in a big box. With no low pass protection it will take 200 watts and hit 108dB at ~50 and the F10 is 20Hz in modelling. They are older amps so the subsonic cut-off is 25Hz using a Butterworth 2 slope so If I use the low filter they will take 300 but you only get another 1.5dB and it is at X-Max plus 10% which is borderline close to X-Damage
Bass boost is a maximum of 12dB at 40Hz on my cheap party mixer so I can only use a third of the amps normal power if I max the bass boost and If I do I can be sure the wallopers will be knocking on the door and telling me to turn it down no matter how many of my neighbours I invite