The 7.3 was a great motor in its day, but you’re now looking at a nearly 20 year old truck and technology.
Compared to today’s trucks the 7.3 is pretty anemic.
I’m sure a new Ram 6.4 or Ford 7.3 gas with the 8 and 10 speed trans would leave the ole stock 7.3 in the dust.
Talking about prices, there is a dealer in the Sacramento area who has clean low mileage older diesel trucks and I’ve seen 7.3s as high as mid $30k.