I found the part number on the kit it is Ford Motorsport/FRPP M-5024-A Stiffening Kit. It had the two bars and reinforcement plates. It may have been standard at some point on fox body convertibles. I don't really know how much difference that it makes, if much. Do you have sub frame connectors installed? If not, that is what I would recommend as I have not seen a kit like the one Ford offered. I would also get a strut tower brace as well if you don't have one as I noticed a big improvement in eliminating any cowl shake. There is more you can do like a tubular K-member, rear shock tower brace and more, but I would start with sub frame connectors and a strut tower brace and see how that does for you.
1988 mustang LX Convertible. Supercharged - Ford Motorsport SVO, Anderson Power Pipe, BBK 255 LPH fuel pump.