"Sound is in the ear of the beholder" (Be-hearer?)
Personally, the catless, straight-thru sidepipe cars that I have heard are ratty/raucous sounding. More worthy of a teen-$200 pickup with straight pipes. The DB level 20" below your ear, and your passenger's ear, is headache-inducing.
We all know that Gen-I cars benefit more from better breathing than Gen-II cars do.
I would suggest the "world highest-flowing" warranteed bullet style cats, and possible a hi-flow muffler...perhaps a stubby, inexpensive hi-flow glasspack, (which can even be rotated 180-degrees to "tune" the sound inexpensively to a civilized ROAR!)
Yes, PartsRack sells the cats, right in your backyard, thanks!
JonB