Big Bucks on '89 Cherokee?

"You're nuts!" the lady at Jeeps Unlimited said when I told her I wanted to replace the engine & trans in my recently purchased 89 Cherokee 4.0L Laredo. "But lady!" sez, I, "it's in perfect shape, 177K on the clock, no rust, it's black and I need something to polish!" Actually, I want to completely restore this rig to better than new. She sez, it isn't "worth" it. Is she right? If so, why? (I am looking at S&S/hiperformance.com engines.)
Also, can I get rid of the radio antennae, put a new player in and hide the new antennae somewhere?
:screwy: