Dude fresh garlic has way better taste, you can use garlic powder if you want to, its still good, but there's nothing like fresh garlic. I wouldn't bother with the spice packet, i'll tell you an easy, tasty sauce for 1 16" pie:
8 oz of Cento crushed tomatoes
a dab of fresh garlic (or sprinkle some powdered, careful not too much!)
2 tsp sugar
a splash of EVOO (filippo berio)
stir it up then spread it on the pie
sprinkle a good amount of oregano, make it finer by using your fingers, then sprinkle pepper, and salt, and a bit of ramano cheese, you can then spread it around a little more, then put your mozz and toppings on.