Yeah, he's serious about the sound playing....
I owned two different Expy's with the 5.4. The first was flawless(other than a very mild weeping from the headgasket at the drivers side rear. for 220 some thousand miles. It got 13mpg but always ran. The second 5.4 was crap to put it nicely. Made very little power, lost it's headgasket, then engine electrical issues. It always ran but very poorly.
I listen to music when I drive and I never noticed increased noise between the 5.4's and the 3.5. I'm not saying there isn't a difference, I am just not put off by any differences.
This is something to consider...
I ONLY bought my 3rd Expy because it DIDN'T have the 5.4 in it anymore.......I would not have spent what I consider to be serious money on a engine I had little confidence in.
Good luck,
jeff