Need some advice on 914-6 issues and value of car, Thinking about buying this car Options

[Matt Callaway]

A 72 914-6 which I have known for 30 yrs is for sale by original owner.
I know the chassis number and engine number are correct - it is a one owner car -and the owner is ready to sell.
No high performance mods - it is original.
It has not been stored - it has been parked in elements for most of that time, but driven intermittently and kept in reasonable enough tune to run.
Body is maybe a 5? on a scale of 10 - not a rust bucket - but would need to be stripped, surfaced and painted. Some metal work would need to be done.
Leaks oil like a sieve -which is my big problem.

I had a 4 cylinder, which leaked from the oil tubes - so I know that is manageable, but I am concerned about other oil leak problems that might be going on.

Any heads up with regard to oil leak problems associated with this engine type, which could be "unfixable".

I would want to do a complete engine rebuild, because it has been "sitting" as long as it has - so I am not avoiding the rebuild - the gearbox probably needs it as well - but I am concerned about getting into a project with an engine that is so far gone it would have to be replaced. I do not want a car with mis-matched numbers, I want to do a historically accurate restoration with matching numbers - or I am not interested.

The owner has asked me if I would make an offer. I do not want to insult the owner with a goofy lowball offer. Any ideas on value of a 5/10ths body with an engine and gearbox that need rebuilding ?

Thanks,
Matt