I put together a comparison of a couple of videos I had to show the difference between flowmaster and magnaflow on my truck...I've got dynomax bullets in place of the rear cats on both clips, so it's fair..lol.
The flowmaster, without a doubt, sounds better for sure...I switched back to the magnaflow after finally getting the cis sound taken care of by the bullets, mainly because the drone of the flowmaster was getting irritating. But after switching, I noticed the magnaflow has nearly the same amount of drone inside the cab, but just not as loud outside the cab. It is a little quieter, but does still have some drone...I can deal with it though since there is a slight difference in performance with the maggy taking the win in that area.IMO the Flowmaster sounds better.
I was running consistent 14.7-14.8's back when I used to have a magnaflow but when I switched to the flowmaster the best I could do was 15.01...I went 2 weeks ago to the track and now I'm back down to 14.7. The only hung hay changed was the muffler, so I guess it does help! LolYou can actually tell a power difference or are you just referring to the Magnaflow flowing better which seems to be common knowledge?