It depends on your engine. For the 4.0L, a starter is about $70, and for the 5.2L, it is $175. I am assuming that you have the 4.0L, since it needs a new exhaust. The 4.0 manifold is notorious for cracking. A replacement header will run about $260 The starter is a piece of cake to replace. Just 2 bolts and the cable and that is it. About a 10 minute job. The exhaust header will take a bit more time but is not hard. It is a pain to get to the bolts under the intake manifold, but you can do it. I replaced my header and installed a new intake manifold by myself last summer. It took some work and I had a sore back for a day or so. Lots of work bent over to get the manifolds off and on again. You will literally have to climb into the engine compartment to get them. 150000 miles is not that much for a jeep. Especially if you have the 4.0L. With proper maintenance, that engine can last 300000-400000 miles.
