Opinions on the Nola Contender please

wouldn't adding two highly regarded subs bring them to the same full range sound as the floorstanders under consideration. Or is it about the crossover and coherence of the sound coming from a transducer housed in the same cabinet? 

This is only my opinion FWIW, but I’d say no to the first and yes to the second.  Adding two subs to your Tylers would yield substantially better bass that the LSAs can produce and probably do nice things expanding your soundstage as well.  And if LSA succeeded in capturing some of the magic of the Joseph Audio crossover, and it seems like maybe they have from what I’ve read in the reviews, then that benefit you’d only get with the LSAs.  I know Tyler makes very good speakers so if you’re happy with their sound there’s a very good argument to be made to just add a couple good subs.  

I guess if I was you and just to be sure I’d try a pair of the LSAs and chalk the 10% restocking fee (if you return them) up to getting better peace of mind you made the right choice.  It’s really the only way to know for sure.  I tend to doubt the Statements are all that much better than the Signatures, but it’s also not like the Statements are all that expensive at their sale price.  Anyway, that’s all I got and hope it helps somewhat. 

I’m actually a big Nola fan, and though I haven’t heard the Contender I’ve no doubt it’s a great sounding speaker.  I will say that I think the LSA is a better overall value since it’s sold direct, and that’s the direction I’d go.  But I’m also swayed by the fact that the new LSA speakers benchmarked Joseph Audio, which are my favorite speakers, in their development so I’m admittedly a bit biased.  FWIW...

You might want to create a new post as this one is 20 years old, but to address your question I’d put the LSA-20 Statements or Signatures high on my list as they go down to 25Hz and will probably fare fine with your amp as long as you don’t frequently crank bass-heavy music.  They are available here on sale by the manufacturer and offer a very welcome (especially these days) 30-day trial period.  The Raven CeLest would be another to give a good look.  Best of luck.