Here's my first impression:

1. 80hz xover sounds better than 100hz because I have better speakers than sub
2. w/a sub I must set the fronts to small to make the sub work...am I missing something? I coudn't set the l/r front to large and the center to small AND use a sub.

I have Klipsch Cornwalls that are spec'ed into the 30Hz range.

My sub is a Cambridge SOundworks 15" 500W sub that isn't as good as today's $1k subs.

My center is a Klipsch KLF-C7 (75Hz) to I currently have the xover at 80...would less damage the front speaker (and not get the bass in the center produced)?

I'd like to buy an SVS sub and put a Heresy on the center and drop the xover to 60.

These are just my first impressions so I'm interested in other ideas.