New owner. A few ????

Hi guys and gals. I just became the owner of a 1996 Tacoma 2.4l ext cab with 171,800 miles less than a week ago. My son just got a 03 Tacoma sr5 trd 2 days prior. I felt like I needed to join this community and greatly appreciate your input and insight. Owned a 94 Toyota pickup with the 22re 5 years ago and I missed it a lot. This truck feels exactly the same from memory. This truck is my daily work truck now (parked the titan v8) and I have a few questions if anyone can help.

Question 1: I don’t remember seeing this on the 22re. Were the head gaskets redone here?looks like aluminum gasket between the heads?

Question 2: what goes here in the blank space?
Question 3: I want to upgrade the radio system. What are you guys using and doing for upgrades?

Thanks in advance.

 

This might help you with some of your questions.

https://www.toyota.com/owners/warranty-owners-manuals/vehicle/tacoma/1996/