Martin Logan reQuests vs newer Martin Logan offerings

Yes, it's essentially the same.  With ML speakers, it's used only for optimizing the bass response. 

I suggest posting your question over at http://www.martinloganowners.com/forum/ if you'd like more responses.

I owned ML's for almost 15 years. The stator panel definitely has a shelf life. I'd communicate with ML about the Requests. If the panels need changing out, that's not a inconsiderable cost.

Ouch yeah good point.  Any idea how much that would run?

Call them and ask!

I started out with ML Preface (non-electrostatic) for my fronts years ago. I quickly moved to a pair of used ReQuests which sounded great passively bi-amped. Currently I have the Summit Xs with their integrated pair of powered 10" woofers. The ReQuests are now my surround speakers. 
The ReQuests displayed a wider soundstage in my room. The Summit Xs are a bit brighter and more detailed. Their main difference is the bass is so much more natural and integrated. I have the Summits powered with a 100 WPC Rogue Atlas Magnum II tube amp. It sounds better than any SS amp I've used.
I am still enjoying the ReQuests with their original panels, but have a spare pair of lightly used panels for backup if needed. If you keep the panels vacuumed, they should last for years. As a last resort, you can pull the panels and wash them. (See Martin Logan's Owner Site).