Keep the YJ, it has more space in it, the TJ's a all plastic in side, & are a smaller interior due to that. Plus, I sure you can find someone in you area with a welder that you could make friends with.... I did an 8.8 Ford Explorer w/ Disc brakes swap in a Saturday + it came with a Limited slip. Hell, I go more places in 2WD now, than I used to in 4WD. I just need to get the Front-end re-geared & locked, then I'll be set. You can do the same, cheaper that buying a Rubi.
That's my 2 cents worth, No Car payment is AWESOME!!!!
PLUS, the insurance is CHEAP!!