Just thinking out loud here.
* Without a swap kit, the Jeep and GM sides don't talk to each other. We know that much.
* Stand alone engine harness gets the Jeep rolling down the road, more or less.
Will the Jeep side flip the fuck out, if it thinks you're driving down the road with the engine off? The brakes will work, the nanny shit wont. I assume something would need to be done with the way the key switch is wired?
Someone smarter, please fill in the blanks.
* AC and cruise can be delt with.
Radio, doors, car alarm, windows, remote start.
All those things, except remote start, will work just fine if the Jeep thinks the key is in acc or run.
So here's my big question. If the Jeep thinks it's just sitting there with the key on and engine off, what's to stop a stand alone LS from driving it around?
There has to be some big glaring reasons why this wouldn't work.