I no longer have high expectations for car audio quality anymore...I am even satisfied with the original setup of the Vios which i hope to even achieve from what i have. But right now i need a new player cause the current ones dead. The problem is the speakers though. My car right now only comes with 4" speakers at the front...the stocks were sanyo lol but i changed it to pegasus components which i want to upgrade. There is no place for bigger ones at the back nor the sides as well..l so im wondering if buying good 4" speakers is enough to achieve satisfying sound? Or do i have to make a back panel thing in the car to add more speakers? Recommend me an entry level player to run the speakers without amps as well. Whatevers the best for budget and i dont think i wanna go more than 1k.

look for (or more than) 50w x4 HU will do the best without amps

yes, a lot of 4" speaker unit sounds better than 6"