Ahh I missed that its a Yj. I had TJ in my head. When I was looking for this stuff i was looking at the OBD2 ecu's.

There appears to be more info out there but still no less spendy solutions since I last searched. Do some searched using JTEC.
More reading:...

I looked into this a couple years ago when I thought a mopar 5.2 or 5.9 swap might be good into my cherokee. I did not come up with anything except that you needed special hardware to program the...