Car looks great!! An offroad x or h will make it much louder. I like 3.55 gears myself. They are easy to find cheap and are great on the street. I used to have 3.27 in my 93 GT and liked those as well.
If you advance the timing at the distributor it basically is a global timing increase. Meaning that if you advance it 3 degrees it is 3 degrees more timing everywhere.