I can't speak for everyone else but my XJ has no leaks at 253,000 miles . As far as the oil filter adapter leaking again after a short period I changed mine about 5 years ago and it's been fine ever since. I took the easy way out and just cut the old adapter off with my sawz-all. I cut across where the red line is in the top photo and as you can see in the second photo that also cuts the head off the bolt which is holding it on. Once the heads off the bolt the adapter just pulls right off and without the tension of the adapter the remainder of the bolt unscrews by hand. I just replaced with a donor from the junkyard off a newer GC which has a LOT more room to get at the thing.