I was thinking the same thing about the Exploder having more insulation. I think they sound too tinny/ricey on 4 cyl's, I dig my Magnaflow XL but honestly I wouldn't even mind something a tad quieter. I'm an old man when it comes to loud exhausts 
Yes, but you must recall that the stainless steel Edelbrock RPM muffler, formerly on said Explorer, served as my frame of reference for this comment. Insulation or not, you definitely heard the Edelbrock droning/roaring in the Exploder's interior back in the day.
As for insulation on the first gens, sure there's the foam under-hood piece. But we've had the panels off all the doors to replace the power window gears and those doors are effectively just big metal cow bells with no insulation. Still, there's thicker shag carpeting, the headliner, underside spare and whatever underside coating that was on the thing. But I doubt it's any match for the low interior noise you might find in later model Explodes.
But all this is just me throwing my impressions out there -- Flowmaster appears to me to have a quiet "performance" product in their muffler lineup, quieter than the products I've tried from Borla, Edelbrock and Dynomax
Will its welds last, will the aluminized paint wipe off? Ask me again in a year or two.
