Klipsch Forte IIIs vs. Heresy III with a sub

I have Forte IIIs but wifey thinks they are too big for our living room / 2 channel listening room.  Considering swapping for Heresy IIIs and adding a sub.  I like to get the really low frequency in stuff like Sylvan Esso but also want the sound of Klipsch for classic rock and jazz.

Three questions:

Will the Heresy IIIs sound as good as the Forte IIIs do now if I add the sub?
Will I be able to cross the sub over to match well with the Heresy's bass range?
Will a Sunfire 8" XTEQ sub work well with the Heresy IIIs?

thanks...