You can also install things like 300M seats, Concorde gauge clusters, chrome shifter if you can find it, chrome door handles and switches, lighted key ring mod.
To make it sound better you could put in a dual exhaust with something like Flowmaster 80s. That's on my to-do list.
There's also throttle body spacers I've seen, but I don't know if anyone here has used them and what they think of them. You could clean out your throttle body, which will improve response if its dirty.