Is this basically what you're running?

Good job. Don't let that hater ruin your CF experience. This is normally a good place.

No you ask how to know if you had a HP or LP D30. Five seconds of searching would of got you the answer. Don't be a *** to the OP. You were just of a newb or even more when you joined.

Honestly the search function here doesn't turn up with great results. You'd have a better chance of finding the info you want on this forum by searching in Google with cherokeeforum: included in your search tag

Well... That's my lack of reading ability for the day

That's site:cherokeeforum.com. For example:
Best XJ exhaust upgrades site:cherokeeforum.com

Each forum has a URL extension. I don't remember most of them, but the old For Sale section was www.cherokeeforum.com/f11
With the right forum extension, you can search your local region, the write up section, for sale or wanted sections, etc. For example, to search for a write up on how to fix the common No Bus gauge problem in late model Cherokees:
"No bus" site:cherokeeforum.com/f51

from my personal observation the 4 liter motors with no cat and loud/no exhaust sound a lot like cummins trucks, minus the badass power and smoke haha

The Cummins would also be an inline six isnt it? Just diesel obviously.

my buddy has a ~$165 magnaflow canister muffler on his LJ (only thing that fit with the rear four link) and it sounds boss. kinda like an old school bimmer straight six. its a bit loud after a while, and he's not the biggest fan of it either but it sounds damn good when you get on it. i'd get myself one but its just gonna get dragged over a rock, so i'll deal with my FM 50.

How hard would it be to remove the cat? Also. Wouldn't the sensors keep the Check Engine Light on?

Difficulty? You have two hands, it's not hard.

Legality and forum rules, you're not supposed to do it or discuss it here. Period.

Yes, you'll get a light depending on your year.

After driving a straight six for awhile, you'll realize why you get flamed for calling it a v6. Lots to learn, young Jeeper. But welcome to the fam

yes , that's my point. no amount of exhaust work will put this motor in the same tier as a v8 soundwise.

Laws differ state to state. Texas for example, a vehicle becomes emissions exempt after 25 years. Until just recently a turbo counted as a muffler and only vehicles burning gasoline as a fuel needed emissions equipment (kerosene and LP were given as exempt examples) so depending on how laws were read by the inspector, you could get away with quite a lot on late model diesels.

Its Federal law... Unfortunately, that will ultimately trump any state law or statue that is in place. It's also on the forum rules we all agreed to when we registered on the site.

Illegal Activity
5. Do not talk about illegal activity on this forum. This includes illegal drugs, parties, wheeling, internet use, etc. Violators of this rule will be dealt with on a case by case basis. This rule includes the discussion of removing catalytic convertors, this is illegal and not allowed to be discussed on this site.