Thanks Punisher, I looked. Chart confirms what I figured would be the case. I like facts.

Here's the Flowmaster, the Magnaflow, and the one they said was best for "drag racing", the Bassani Real Street. Figures are Horse Power followed by Ft/Lbs Torque. I didn't copy and paste every step, just every 500 rpm step.
http://www.mustang50magazine.com/tec...o_numbers.html


at 3000 FM 140.0 245.1 MagF 143.8 251.8 BasRS 107.2 204.7

at 3500 FM 189.4 284.1 MagF 189.4 284.3 BasRS 177.1 286.2

at 4000, FM 213.2 279.9 MagF 215.8 283.4 BasRS 208.3 291.8

at 4500, FM 271.7 317.1 MagF 274.2 320.1 BasRS 244.7 302.4

at 5000, FM 306.6 322.0 MagF 308.8 324.4 BasRS 295.5 326.8

at 5500, FM 347.4 331.8 MagF 348.2 332.5 BasRS 330.8 330.9

at 6000 FM 369.4 323.3 MagF 370.6 324.4 BasRS 364.1 332.6

at 6500 FM 363.7 293.9 MagF 369.1 298.3 BasRS 373.7 314.1



................Decibels At Idle ... Decibels At 2,000 RPM ... Decibels At WOT
No Muffler...............91.................103...... ..................Max.
Flowmaster..............82..................93.... ....................115
MagnaFlow...............82..................91.... ....................114
Bassani Real Street.....84.................96.................. ...... Max.

Yeah, your right .... there's a couple HP and Ft/Lbs Torque in some places to the Magnaflow's credit, but the "Slowmaster" seems to do better in the real world range than their "best drag race" muffler and stays within a couple HPs of your Magnaflow. Sure, Wade's may rust off in 2 or 5 years as may the one that came on my truck and which was near new.

I see no compelling reason presenting itself in that chart for pulling it off before rust gets the best of it. If I pull it off now, it'll lay in the pile and rust anyway and in 3 years I'll have a 3 year old Magnaflow ...
... where as I can just get the good out of this "Slowmaster" for a few years, enjoy the welded system that has the tips perfectly placed and then have a new Magnaflow then.

As to decibels, I already added another type ahead of it to kill droning and mellow it out, so I'm happy knowing my system is dang near as good as a Magnaflow and better than a "drag race" muffler.

I don't know about your 4.6, but my 5.4 will probably never see 6,500 RPM as long as I own it. I maybe saw 6,500 a couple times in a CVPI and then ony very shortly as it was when pulling North Mountain WB in a pursuit likely. Normally, I let the car do it's own shifting and it did so about 5,500-5,700.

.... the drink of real "Troopers".