several systems ago, i used a pair of entec lf-20's mated to ae-1's. this was a fun combination. the speakers played very loud and the front-firing entecs slammed me in the chest as tho i were at a rock concert. the entecs were fast enough to keep up with the ae-1's and went very low. i replaced the entec's eventually with a muse model 18, that i used with the ae's and, later, avalon eclipses and ascents. the muse never had the slam-in-the-chest feeling of the entec's but was much more musically satisfying than the lf-20's.
i've auditioned the watt/puppies in a number of iterations. i hadn't been too impressed with them until i heard the 6.1's with an all-nagra frontend, including a reel-to-reel playing 2nd generation masters. this combo was very impressive. the watts and puppies were completely coherent, as if they were a single 3-way. i can't imagine that the 6.1 watts would sound close to as good with entecs. i doubt, as well, that you would be completely satisfied with lf-20's either, unless you are looking to extend the bass output without regard to speaker coherence. but then, i've not done a real world audition, so my opinion is necessarily an assumption. you may well find the watt 3/entec lf 20's to be the best you've ever heard. i do hope you can listen before buying. BTW, were i in your shoes, i'd spend my $$ upgrading to a newer version of wilson stuff or try out some other full-range speakers. -kelly