In short, this thing works. With the AFSB installed in place of the stock roof panel, a quick drive was revealing. Creaking and rattling were notably diminished, as was vibration. And as for body flex...TTR's Ray Davis was on hand when we tried out the bar, and Ray encouraged us to take the '84 through a steep driveway or two. Not only was body flex reduced-a lot-but the "C4 Driveway Double-Creak" had also disappeared. The change was impressive, to say the least. It's as if the "hinge" Chief Engineer McLellan mentions was locked into place, unable to move...which is what we'd guess he had in mind when originally designing the C4 as a T-roof car.
We haven't had a chance to autocross with the AFSB in place-yet-but Davis, a rabid racer himself, assures us that the bar pays dividends on the track, as well. "There's improved visibility, less heat, and more headroom for a helmeted driver," Davis told us. "And the bar structure ties in the front of the car to the rear, so there's no flexing." Tom Gasper assures us that wheel hop is also reduced in racing situations. For those looking to find out for themselves, the AFSB has been approved for use in several types of SCCA and NCCC racing events.
To that, I'll add some personal observations. In addition to the aforementioned noise and flex reduction, my '84 just felt tighter and more solid while equipped with the AFSB, and even more surefooted when cranked over in a turn. TTR's website claims that the AFSB "plants the tires to the ground," and "stiffens your suspension during cornering," and that's exactly how the car felt. And, for the record, the stiffness and noise reduction provided by this bar far exceeds any rigidity provided by the factory roof panel. If I had a garage to park the car in at night, I'd be sorely tempted to put the '84's roof panel aside for the summer and do all my driving with the AFSB in place.