If there is some emotional attachment that you have to keep it yes. Otherwise it is not worth it.

Not really. Cost of restoration will exceed the value of the car many times over. If you have some really strong sentimental attachment to it, only you can answer the question if it's worth restoring.  

Financially no, those 4th gens arent worth a whole lot even with the LT/LS1. Depends how much you like the car. I have a 2000 V6 that I plan on doing a ton of work to. New suspension, building another engine, upgrade trans... but im doing it bc i love the car & for my enjoyment. Those things are unibody's so if the body is rusting that its really not worth it unless you can handle alot of welding.