Walkers are often overlooked but are louder than Thrush, Raptor or Pypes turbo mufflers, and Pypes Race Pro or Street Pro might be up your alley.
Dynomax and Walker are not only owned by the same company, half my Walker parts are identical to my Dynomax parts (pipes, various styles of clamps, hangers, etc.). Definitely not saying the mufflers are all the same but they offer a good sound at a discount.
Flowmaster 40s aren't as loud as 44s but every single one of them drones. Period. And they do it much worse than the Jones Full Boars on my Cutlass, which hardly drone at all and likely won't once the interior goes back in. It's just a Gen 1 305 though. The same mufflers sound even better on the 4.8 in my '04 Sierra, which is roughly the same displacement but everything concerning air/exhaust is different. They're louder than some Flows but not every series, and can be purchased as Lawson Incinerators but you'll overpay and just get Jones anyway. It's a bullet style single chamber with divider, no packing, and is a copy of an old school piece I can't remember at the moment.
Ya really gotta ditch the manifolds for a great sound, even if you have the truck or Vette units that are like shorties. The longer primaries will drastically change the note, as will an extremely free flowing intake.
If running a crossover then you may consider an "H" as opposed to an "X", as the "X" will quiet things a touch and occasionally introduces a slight "whoosh" sound. I feel that it hurts velocity as well but that's just my opinion.
Borla sounds too metallic for my ears, can't recommend them.
Magnaflows can sound good but don't have the old school tone. Flowmasters get you a couple more HP, though not the 70 which has your exhaust bouncing off of 7 walls. Chambered muffs kill power in general but multiple chambers, obstructions, or sound diverters really hurt.
You keeping the cats for that 5.3? Cuz they make a huge difference even though they're basically all high flows now. Again the '04 sounded like 2 different vehicles when the cats weren't in place- the honeycomb structure has an impact on both the airflow stability and the tone quality while not impeding flow like the old style did. Straight pipe with cats was much easier on the ears than no cats at all, and the difference when combined with mufflers was easily noticeable. They seem to cut a bunch of the high tones, hiss, and cackle.
Check out
https://moderndaymuffler.com/ for the lowest prices and
https://www.mandrelbending.ca/ for affordable mandrel bent stainless, both shipped directly to your house.
Also, don't be afraid to pair a 4" to 12" straight through glass pack with a race muffler to achieve a deep tone with great flow and minimal hiss.
