There are only 2 cats. One on each side before the y-pipe. As far as I know, as long as you have both cats, and a muffler, or a pair of mufflers, you're 49 state legal.

In Missouri, we have visual inspection. We have to at least look like we have cats, mufflers are optional. I'm running true dual 2.5" with X-pipe, no cats, and dual magnaflow mufflers.

 

Absolutely no need for true duals on a 4.8, unless of course you are going all out with forced induction. As stated it will kill your low end.

That being said, a single exhaust can sound great, i was running a magnaflow 5x8x6 race seriers 3" in/out muffler in stock location turned down after the axle on my old 07 rcsb 4.8 and it sounded incredible for running all the rest stock exhaust components.

 

I don't understand why everyone is saying true duals will kill low end. The whole backpressure thing is a myth, from what I've read. And if you're adding a x-pipe, you're balancing out the exhaust. Mustangs with they're tiny 4.6 have true duals. He's adding mufflers as well. So it's just opening up the flow more and will sound better. Idk, just my opinion

 

Backpressure waves effecting flow aren't a myth. Just that they are tricky to 100% understand. I understand the concept but not near enough to make any judgement calls of their effects.

Unfortunately my refrigerator has been crapping out on me this week & I just bought one online tonight. Couldn't put it off any longer so that means the exhaust purchase gets pushed back until next month.