I would like some advice on what type of amp I would need for 4 x 90 watt 4 0hm speakers and a 150 watt 8 0hm subwoofer. It's only for a smart car so nothing too expensive. Just decent sound thanks.
A 5-channel amp will do just fine. You won't get 90W per channel for the speakers, but it isn't required, in case you were thinking you need to match power ratings. Check out the JBL GTO-5EZ.