Rough call mate. You’d be better off posting his in the present 90’s onwards EJ forum
My biggest question would be who rebuilt the engine and did they know what they were doing?
For your first car I’d be going for something that’s stock, reliable and easy to maintain. With this you’re buying a whole lot of aftermarket gear that you and your son most likely know nothing about, nor would you know what’s stock and what’s not - that doesn’t make it easy to follow up replacement parts. Lastly, yes it looks awesome, but you could be buying someone else’s problems which is often the case with highly modified and raced vehicles unless you know the vehicle from being at races/in the owners circle of friends.
Cheers
Bennie