With a borla cat back, no pre or main cats, i get very, very little rasp. It shouldnt sound bad at all if you have a decent cat back.
If youre taking the precats off and making mil eliminaters, you might as well just put in a straight pipe or off raod y-pipe instead of a high flow cat. As stated, I dont think just a high flow would get you that much, if any extra power. From what I've read, the stock one flows fine.
