It will be the oil seal which is part of the rocker cover.
You can replace the seals, however, I have in stock new covers which come in cheaper than the oil seal kit.
Just drop me a PM if I can help further:
Very straight forward on a ramp and doable in 4 hours if you know your way around a 350Z.
Best to have a look at the clutch and fly when you are in there.
Go with the replacement key option.
There are cheaper alternatives for the keys and I am sure someone will be along shortly to advise on the procedure.
Unfortunately, the N/S A pillar trims that I have are damaged I am afraid.
Also the front roof weather strips are in great shape but they are extremely difficult to remove without distorting the shape.
The 2007 engine will probably be the rev up.
Make sure that you do not buy the HR engine as there are expensive fitment issues.
PM me the link for the 2007 engine and I will advise.
If you have the rev up engine you could fit either the rev up engine or the earlier DE engine.
The earlier DE is the better engine.
You can transfer a DE tune across into the Rev Up ecu and turn off the DTC this will be required when fitting a DE motor into a Rev Up.