Based on your situation, I believe a REL subwoofer would be a good fit (specifically, I'd look for a subwoofer with speed). The model that you will need would depend upon your room dimension. There are some trade-offs when using a subwoofer but it is my personal opinion the benefits prevail, especially in dynamics and bass when a speaker needs a little help in those areas. You will need to do a little work to position the subwoofer in the right place and to dial-in the crossover.
There are many threads that you can refer to for more opinions concerning your question. Good luck!
There are many threads that you can refer to for more opinions concerning your question. Good luck!