i went to flowmaster.com and listened to the sound clips. super 40 sounds way good!!! 50 is quiet. 40 sounds ricey. thats where you can check what you want, hemipwr07.

 

I have a 3in 10 series flowmaster. I went from a 3in dynomax ultraflo (one of the best flowing there is) to the flowmaster. I didnt lose any power at all when i switched. The 10 series is their race muffler, and is probably their best flowing design.

I would recommend it if you want a very aggressive sounding muffler. Its just about as loud as a straight pipe, but still has that flowmaster tone. Another big plus isthe price. Mine was only $75 new from summit racing.

If its power youre going for, then have a shop run true duals. Its easysince you havea cat on each side. All a shop has to do is cut the pipe just before the Y and run 2 separate pipes side by side. That will sound and flowway better than any Y pipe setup.

Heres a clip of my 10 series:
http://www.youtube.com/watch?v=sm8IuF0yfak
Its louder than it sounds in the vid.

I plan on going true duals with another 10 series and an H pipe soon.