Help needed with car Stereo upgrade, I'm a total noob!

[Ajsski99]

Hi all, i currently have a 2008 ford fusion wth the large black sony head unit (Picture attached)

im looking to upgrade the 4 door Speakers and also maybe add a sub in the boot.

what would i need to do for this? im sure the stock head unit is powerful enough for some mid range aftermarket door Speakers but if i want to add a sub what will i need to get?

if the stock head unit isnt enough, i was thinking of upgrading to one of those android tablet head units but would also need some advice on where to find one that would fit and wiring advice as i assume its not just plug and play

all responses are greatly appreciated and excuse my ignorance, i have no idea what im doing!

[Hardcore79]

Change everything you'll need a double din trim and then do your homework on the wiring in the process of changing mine and my fusion had same as you pictured I took to halford who in all there wisdom cut the stock harness off and then said o I've never seen these colours before so get the correct harness or do your homework coz in the car there are 2 yellow and brown wires 2 green and black and 2 orange and black and on mine go to different things