I drive a grand marquis if you'd like me to tell you about it.
@previous (postmortem)
Did you supercharge it? I'd go for a Twin Screw supercharger from Whipple, Sprintex or Kenne Bell.
@OP
I'm hardly an expert but it sounds like SLP II loudmouth mufflers
@previous (Meta !PARAdoxiHw)
I just watched the whole video. I feel dumb :/
Yes, it's a Loudmouth, but with other things. I really wonder what it would sound like with 180-degree headers.