Sorry - but I have to respectfully disagree - 2002 did not correct issues like the leaking differential, column lock, sticky fuel sender, rocking seat, etc.
There are fixes available for all of the mentioned - some from GM, others in the aftermarket.
I do agree however that one should purchase the newest and lowest mileage car that is affordable, but I would not hesitate to purchase an earlier low mileage car. Make sure that the car is thoroughly checked out by someone familiar with C5's.
Overall the C5 is a great car, the LSx series motors are tough and strong, and can be modified to make lots of power, without sacrificing durability. The chassis is very stiff - and as a result -most of the creaks and groans that were prevalent in the previous generation cars are gone. The new chassis was designed from the outset to be a convertible, so all three of the body styles are very stiff giving outstanding handling characteristics.
As a highway cruiser, canyon carver, track/autocross car or drag racer - the C5 is a very satisfying car to own. Good luck with your decision.