Maggies and Subs - REL vs. ACI

I am a using stereo pair of Sunfire Signature subwoofers with my MG 3.5/R with excellent results. The blend is seamless when the subs are configured and positioned properly (the subs must be kept away from room boundaries for best resutls).

The Force is one heck of a sub, it would make an excellent match with your Mags.

The only sub that I found quick enough to keep up with my Maggies is the Talon Audio Roc

You might want to look at the Sunfire Architectural Signature Subs. I have two mated to my 1.6 QR's. They are astounding in sound quality too.

Ditto w/Kck. Maggie 3.6's mated to a REL Strata III, against a wall, not in a corner. Excellent. No experience with ACI subs, but very very very happy with the REL/Maggie combo.

Not tried the ACI but had considered it until I found a good deal on a REL to go with my 3.6s. Was very happy with it for two years or so, when it was in a corner. Then I changed to a higher-res CDP and thought the bass was undefined and bloated. Moved the REL out of a corner but kept it near a wall. All is fine again.
The REL may be the one item in my system I have never had issues with and would not sell it because I would simply have to buy another at twice the price.
REL is widely reputed as being THE musical sub to go with Maggies. Maggies need a v. fast sub and the REL supplies that.
Sorry can't help with the ACI but I believe they have a money-back deal. Also Tweeter/Hi-Fi Buys sells REL and their refund policy is good. If not one in your area I think they will ship, but return may be difficult in that case.