What is the difference between unleaded gas engines and leaded gas engines?

Answer 1

Engines built to use leaded gas generally had higher compreesion ratios that made them more powerful. Unfortunately, the higher compression ratios need higher octane ratings to avoid detonation or "knock." These higher octane ratings in gasoline were achieved by adding tetra-ethyl lead to the gasoline. Lazy engine designers also started relying on the lubricating properties of the lead to reduce engine wear, so these older engines may be prone to rapid valve-seat wear even if you feed them high-octane unleaded.

Answer 2

The only way to really find a great deal on a computer is to shop around. Pick up flyers and search the web. You don't want to buy a computer and find out another store had it for less.