Ok. There are a lot of options for head units. What u have is what they call din and a half. In my 03. I installed a pioneer app radio
image-200297205.jpg
It did require some resizing. I used a dremel. I Made a template and just followed it. Fit perfect when I was done. I'm a apple guy. So that's why I went with this radio. I had no probs and really enjoyed it. I had no problems using any apps in my phone to play music or vids on the screen. As far as a sub?
image-1288728386.jpg
I purchased this 800w 10' sub. 110$ on amazon.com. I put 500w to it. And it handled everything. I was looking for that deep bass kick for a bass drum. And I got it. It's very small so it fit under my back seat. My 03 was a super cab. I still have it. And plan to install it in my new truck. There are many options out there