I'm waiting on the Gyre FX-130. People selling the mp40's like hot cakes....gotta be a reason.
I'm in the same position as you, with a 36" 66 gallon. Decided to go with a single MP40 for now, and maybe another down the road if need be. Reason being, Ecotech has a proven product that is reliable and is backed by great customer support.
From what I've heard CoralVue provides decent support, but the QC from Maxspect seems to be lacking from what I gather on the big Gyre thread here. IMO, the MP40 was the safe choice while the XF150 is a bit of a gamble.
Gyre replaces 2 MP-40's not 1.
I talked to one Guy that Sold $1,000 worth of Tunze's and says he gets better Flow with just one Gyre than all those Tunze's.
Are you telling me that the one grye can replace my 2mp40's on my cube? 48/48 inches wide?