Those are the top-of-the-line Bostons and mid-low end Quarts so I would hope that the Bostons have a better crossover. Any particular reason that you want a 3-way system? A 2-way system can sound just as good and sometimes better and takes less space and effort to install. For the same price as a mid level 3-way system, you can get the high-end 2-way system from a company such as CDT from the Zeb for example. Many of the really high-end companies don't make 3-way systems in their high end lines because with a good enough midrange/midbass, two speakers can cover the whole frequency range (minus the sub-bass) and fewer speakers, means fewer phasing and cancellation issues to deal with. The only real benefit of a 3 way system is when you are trying to match your high frequency set-up to a really powerful sub system and you need a dedicated midbass that will be making the tranistion between the subs and the mids. To make this work optimally, you will have to have a dedicated amp for the midbasses and cross everything actively. If you don't want to go that route, I would suggest getting a 6.5" two-way set. Your $600 will get you into a higher class of speaker in a 2-way than a 3-way and I think you will probably be happier.