Small sub enclosure

I've built a sub enclosure that is too small.  The space available in my car has dictated the size of the box.   I have an 8" Clarion SRW2081.  The box size is .28 cu. ft. (with displacement of the sub factored in).   I do not have any other components yet.   Any idea how this sub will act in this sealed box.   I have zero experience, so I don't know what to expect.   Would the sub need more power, or less power in such a small box?  The sub can handle 300w max, and should be in a sealed box of .48 cu. ft.  This box is positioned between the occupants (2 seater), so doesn't need to be very loud.  Any suggestions as to how much power I should shoot for when selecting an amp to power this thing, and what to expect, would be greatly appreciated.  Also, is there a crossover point that is safer when dealing with a too-small box?