A good bookshelf will perform better than a cheap floorstander as you suspect and can hold their own against even many good floorstanders, you do need good stands for bookshelf speakers so you must keep that in mind in your choice between the two. That said, if you like the sound of Paradigm 100's (I do)...you won't find many or maybe even no bookshelf that can outperform a floorstander of this size in shear weight and output. With a sub that is well matched to your speakers and room you should have no problem surpassing the Paradigm.
Dave
Dave