Sorry...didn't clarify my question before I hit 'post'. What I meant to say is "why are they ridiculous if they have been engineered for the appropriate back pressure in a stock setting and street driving?"

On my other Mustang, I replaced the exhaust with a system that included hi-flow catalytic converters, which helped retain the low-to-mid range torque curve. If I had no converters, in addition to flunking the emission checks in my state previously, I would have experienced more power at the upper end of the rev range, and a loss of torque down low.

For street driving, that type of a feel seems like a loss, rather than having more zip on the top end.

Thanks for any additional comments.

 

Crap those things are restrictive. There might as well be nothing in my Bassani comp cats.