4runner,
You are in the same boat as most 914 owners.
Fortunately, you have a 2.0L; a great place to start.
1. Change your oil.
2. Siphon out the gas and refill with new gas.
3. Buy a new battery.
4. Try and start it.
Don't worry about how long its been sitting.
These motors will run forever. They are brutal. The fuel injection system is the weak link. Are you still running fuel injection or did someone switch over to a carb. I am a strong supporter of carbs. Delortos are my drug of choice. The bigger (40mm or 48mm),... the better.
Secondly, Sagging ass is one of the many problems that plague these little cars. The rearend is easily shimmed to get it back to snuff. If your interested how, just ask. It won't be exactly a short answer.
Consider it,
Dave
PS I used to work in a Porshe repair/race shop. I owned a 916 replica.