do i really need an amp?

[new2bmw]

hey guys, had an amp hooked it up today and it has an internal short so i need to take it back. Question is do i even need an amp? i am using a pioneer DEH-3800MP continuous power 22w per channel 50wx4 cd headunit. For speakers i have factory 5.25 in the front and pioneer 6.5 160watt max 30 watt nominal in the rear. do i need to get another amp or should it be clear enough and loud enough without it? if i just get my cash back i can buy some maintenance stuff , i just want a system that sounds good and has a reasonable amount of power for those rides when i feel like i am 19 again lol.
thanks guys

[Addissimo]

If you're running cheap speakers... i'd say ditch the amp go off your hu.