Brooks Marathon Training Shoes

So I am less than 3 months away from my 1st marathon and am getting up there in distances.  I did 18 miles yesterday which was 3 miles longer than any run I have ever done.  My question is about shoes since it is all about the shoes.  I am loyal to my Brooks brand, and love my Adrenaline GTS 12.  However, I was wondering if any other Brooks runners knew of possibly another shoe under their label that might be better suited for the distance training?  It's not that my Adrenaline's are giving me trouble, but as with running in general I am looking to always improve.  If there is another Brooks shoe someone finds better for marathon training I'd love to hear about it.  Or maybe the Adrenalines are the best and I will just stick with them.  I am throwing this out to all of you.  Thanks in advance for your help/advice.