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Amsoil website has a great product application guide that gives you the recommended weights and capacities for all vehicles. I looked up a 2000 Civic, and it gives the oil capacity as 3.5, 3.8, or 4.2 quarts, depending on which variant of the 1.6L engine you have. It shows that 5W-30 is the preferred weight, but 10W-30 is okay if the ambient temp is above 19 deg F.
I personally use Amsoil in all my vehicles and small engines. Besides lubricants, they also make excellent oil and air filters.
The most important considerations for lubricants are proper weight and SAE specification. Brand names and choosing between synthetic/mineral are less important.