while i don't have a v6, i have a 4banger under the hood, i fully totally regret taking my factory cat off and replacing it with a thunderbolt, sounds like **** and it allows the raspiness to go through. There wasn't anything wrong with my cat, i guess i should've done some more research before i went cutting anything. Now I know better. Coupled with my Magnaflow, it's basically almost straight piped just not as loud.
Mind me asking, but what's hpw? -Mike-