Looking some advice on a 2002 380 avenger. Are they quality boats? Going to be doing fresh and saltwater use it. Will this boat with a pair of HP 500 EFI run high 70's low 80's?

PQ's are built tough, built as well as anything as far as structure goes. I've had 2. I'm not 100% sure on the speed, but judging by a friend who has one with 525's, I would expect upper 70's.

75-77 GPS on a great day maybe a little more

boatnt is correct, a lot depends on fuel, weight, and water conditions. As far as ride, one of the best out there! I too have a 2002 380 with 500 EFI's