I guess I will take a different viewpoint to many of the other posters... I believe there is nothing wrong with your front-end at all... Aragon's older amps are fine, IMO (the newer ones aren't too bad either). I really don't believe you are missing much (if anything) there.
As for speakers, I prefer the Linbrook Signature System to all except the Montanas, as I have not heard them. I will say that the Linbrooks are going to be tough for the Montanas to beat though (even though I am sure they sound superb), as the Tylers have tremendous high quality low bass that few speakers can touch anywhere near their price range. That coupled with a crystal clear midrange and natural sounding highs make them a good choice to my ears. I power mine with a Cary Preamp and Aragon amp, and the combo works just fine, BTW.
Good luck... They are all good speakers,