Not sure which 1991 Ford Mustang In-Line Modules are right for you? We have over 1502 customer reviews, with an average rating of 4.5, to help you find exactly what you're looking for. Here's what some of our customers have said:
"Due to my mods on my 91 GT, the JET chip gave my mustang more responce right away." —Thomas W from Hesperia, CA bought a Jet Performance Module for a 1991 Ford Mustang.