It's a temperature thing, so however far down the line where the exhaust is still at least 500° would work.
I deleted my cats when I got headers. The sound (note, not volume) is the only part I like about them being gone. Other than that, catless kinda sucks, IMO. The exhaust volume is so much louder and the smell is thick and nauseating. You can't idle or drive with the windows down as the currents seem to suck the fumes forward. Seriously, the exhaust seems to defy physics just to get inside your car and soak into your clothes and interior. You have to wait until everyone is in the car with the doors closed before starting it. I mention this because I'm outnumbered by females in my household. When we're all about to go somewhere, they all realize at the last second the things they forgot and have to go back in the house. Once they've finally gotten all their stuff, then they all gotta get back out to go pee. Sometimes there's an emergency makeup fix. Every time they get out to run back in, they leave the doors open and the fumes flood the cabin. This BS has long been remedied, but I wanted to mention it to reinforce just how much of a nuisance going catless can be since you have to alter your life to accommodate it.
After losing the cats, it took 40" of muffler to quiet it back down to where I like it. Before, a simple 18" straight-through muffler was perfect. I have some Magnaflow cats that I'm considering installing into my Y-pipe.
All the tune would do, as far as the deleted cats, is turn off the catalyst inefficiency codes. You might be able to have the idle tune adjusted to run lean or whatever to reduce the smell when idling. But, all other instances still apply.