Hello everyone, Ive had my Mustang for about a month now and am new to the Forums. I've done a little bit of work on my ride so far and plan to do more starting with coils. I've done a bit of research and found on american muscle the screamin demon is a hit with 5 stars and 22 reviews for $89. while the GMS is $154 and boasting that it adds 18+ horsepower, although it has no reviews. Is there a reason people are staying away from the GMS even though it appears it would add more power. The Screamin Demon doesnt mention how much horsepower it adds. Really appreciate the feedback!