well they all have strengths and weaknesses. but if it was me and i had it to do ove a 97 - may of 98 tj with the 4.0. they put out the most power and best airflow. after that the head castings was weak and cracked. i would say cherokee but they have a unibody that has weaknesses.as well as the grand cherokee. Now with that being said the best all around would be the rubicon with the 4.0. it has dana 44s front and rear and a good strong transfer case. its a shame chrysler went and ruined jeep with the v6,the liberty and these gawd awful soccer mom rides. maybe the company that bought them will straighten them out