Sir very nice SUBs, "Dubai mein sub milta hai", viva la Dubai.
Sir they will work great in a 37hz box.
But then again if you have enough space why have you opted for the F type ?
the 308f are meant for free air use,
depends upon ur liking, if u like the sound rite now stick wid it
I would advice you the same.
You can comfortable go as low as you can as long as you have the Pioneer AMP paired with SUBs.