Well, I went and did it. Bought a set of ATSF F7A&B from my local hobby stores. I went in and saw them on Saturday when the first came in and liked what I saw. I didn't buy them then because I didn't want to fool around with another coupler exchange! Fancy that! Anyway, I took them home Monday night and ran and ran and ran them. The B unit is definitely faster than the A unit and has the "Flying Chief" logo on the side. Both units are powered and the grills are etched, rather than molded. All in all a great purchase.