I think the 3.6s will probably sound great in a room that size - they need room to breathe. (At least, my 3.5s needed more room than I could provide). The Power 3/Line 3 SE is a terrific combo, but as others have noted you might need more power for high SPL. If you're willing to consider replacing the amp (should that prove necessary) or adding subwoofers to relieve the Power3 of the heaviest lifting, I'd be inclined try it before concluding that it won't work.
Good Luck
Marty
Good Luck
Marty