I'm looking at these to mufflers for my Chevy 350. Both claim to reduce interior resonance (drone) compared to original 40 series Flowmasters. From the site, the Delta Flows are the quieter of the two. My question is which will make the interior of my Nova liveable on longer trips. I love the deep sound of the Super 40s but do they really reduce drone over the originals? Are the Delta Flows too quiet? Any experiences with these mufflers over the original 40s is welcome. Thanks.