I had a 2.5l on 35s and the biggest help was regearing the axles. I went from 3.55 to 5.13s.
Now I also did an engine swap on my jeep. I swapped a '96 4.0l in place of the 2.5l and did it all for around $250 all said and done (including stuff like new oil, coolant, motor mounts, thermostat, spark plugs, etc)