99, in my opinion, is the pinnacle year of the xj. If you were to sell I'd recommend fixing the steering & brakes otherwise you'll find more low ballers, but with that said, your mileage is good, the mods would be seen as good to some and meh to others. The clean XJ's are going for a premium these days, I'd say anywhere from $3,200-5k+ in my area.
But, they're only worth what someone is willing to pay.
Here's my situation. My brother bought it about 2-3 years ago from a dealer for $5,200 stock for his first car. It had 92,000 miles then. He got the 30 day/1,000 mile warranty with it. Within the 30 days, both o2 sensors, and the tps went on it. They fixed that for free. Then with like two days to spare, the head gasket went. He got that fixed for free.
So basically he got about 1,000$ in repairs for free. I now don't worry about the head gasket going anytime soon.
They also put in a whole new exhaust system. I don't know why they did it, but they did.
He's going to sell it to me, because he wants to get a ZJ. He originally wanted to get $4,500 from me, but after realizing that i was going to spend around 500$ on new steering and brakes, he dropped the price to $4,000.
He's also happy to see that it's going to stay in the family.
Do you think $4,000 is a fair price?
If i do buy it, i'll throw up a build thread as i have a bunch of plans for it already.
I'm currently sorting through the minor problems it has, and getting the fixes for them before i acquire it.