Well not really horsepower per say but you can feel it on the road!! For us LX owners with the 1.9SOHC, I did this playing around and it works. on your throttle body, where the cable is connected, (bad explanation but bare with me), the throttle stop is actually on the pulley. If you open the throttle all the way you can see what I mean, where it stops. Take a pair of pliers and bend the stop back to where it wont touch and thats it!! I know it looks like its closing the other way but my 93 LX has been up to 120mph with no other mods except the airbox silencer removal. A it easily revs to 6K like it used to rev to 4!! Try it and see if it just worked for me.