As far as matching quality and ability, you could simply refer to drivers used.
Are they the same drivers used in the mains?
Are they the same size?
Is the speaker a similar design?
Are the specs closely matched?
If all of the above are answered yes, and you find the pair that suits your taste, then you should be in good shape.
Speakers are the mostly debated products on this forum. What matters most is what you like.