BigO,
Since you expressed budget as an important part of the equation, you must include amplifiers in your decision. HLCDs have horn tweeters that can easily be 10 dB louder (like at least twice as loud as you perceive it), however, their midbass drivers typically have larger midbass voice coils resulting greater power handling but also lower sensitivity. Thus most HLCDs require a larger amplifier. For example, to get the speaker's full potential, a Wetsounds Icon8 might package with an amplifier having 60% the power of an amplifier that would package with a Wetsounds Rev8. So look at tower speaker costs in the context of the package. Not knowing exactly what amplification you have now, it's unlikely it will translate to a tower speaker upgrade.