I haven't heard of too many folks having a problem with the mainifold leaking with the 2.5, but thats not to say they have a common issue. The 4.0L for YJ's seem to go over time, and it is a somewhat obvious spot, where the front three and back three come together on a header. There is no way to repair it on the vehicle and taking it off and rewelding it can cause all sorts of mis-alighments and warping the mounting surface. I paid a shop to replace it on mine rather than dealing with sticky bolts/studs on the intake/exhaust. I'd go to a local muffler shop and get them to inspect it and give you a price for them to provide parts and do the work and see what they say. Then look for parts on-line at places like 4wd.com and others like them. Ebay does have a lot out there, but some prices for used stuff after delivery fees added in can be just as much as a new one.