welcome to the site. nice car good choice
I would do a nice system. ( something that can be removed if sold ) a nice fiberglass sub box and am rack color matched to the car or leather matched to the seats would be awsome. also I would put a final 500 with your car number in a lit plexy center piece in the trunk.
clear a set of head lights and color match em to the car.
body mods- No
set of springs to lower it.
winter set of steels so the final 500 wheels stay pretty