Andrew, the V8 swap is cool, but not for the faint of heart. As far as the 5.2 swap goes, you can do it, but you will have to move your tranny forward and there is no way that XJ radiator will work. It will take some expensive custom radiator or redo the cross member and use a ZJ radiator and ZJ cross member. Now as far as that goes, there is a problem with the dash stuff working etc. The best thing I can suggest is follow my thread on Project TJ Resurrection. I am currently installing a 99 4.7 from a WJ into a 98 TJ. In order to make your electronics work, it is far better to keep to the same year or nearly so. Also plan on getting some factory service manuals, mine are on CD. There is some wiring to do and if you do it using these you can keep it real clean. But still you will have to fabricate motor mounts etc.