Off road vs catted LTH probably less than 5hp difference on NA car. Sound wise off road louder and added raspiness.Thanks very much for the info. Appreciate it. As mine is a DD and will be on E85 and 93 when forced to, I guess maybe catted would be a better option for me. Maybe will look into the LTH high flow cats/headers.
LTH added to e85 is definitely worth the power increase. Your in for a pretty significant volume increase as well. I started with Corsa Xtremes and added catted ARH LTH. The tone got too trumpety for my taste so added a pair of Vibrants. That cleaned it up some but ended up cutting off the Corsa mufflers while keeping the double x and added AWE Touring rear end. I would put that combo as a bit louder than the original Xtremes, but with more character in the lower rpms. If you have the full AWE catback with the resonated H it will be a tad quieter but still going gonna scream up top when you add the LTH.