The J30 was a nice car.  It already has lasted long.  What you should be
concerned with in buying a 13 year old car with 148k miles of any make or
model is what its condition is now.  Are there any maintenance records?
Does it look like its been used as a rolling outhouse? Why does he only want
$2000 for it, as they were in the neighborhood of $40,000 when new?

The J30s use a version of the V6 engine from the 300Z.  It has a timing belt
that requires periodic changing.  There are a number of "Z" groups on the
net.  You could browse a few of them and see what sort of discussions are
going on about the engines as they age.