Carbon fiber hood and trunk lid. That's about it in addition to what you've already done... unless you want to swap the front seats for racing seats.
Fiberglass rear quarters? That doesn't sound very stable... how do they mate up? By the end of your little fiberglass spree, you're going to be driving a car with the safety of a topless Honda Insight.
If you supercharge your six, you won't need the fiberglass quarters. I'd shy away from that in a heartbeat... especially if you have fiberglass fenders. What's left? The roof?
(Oh, god... I'm giving you ideas!)
Keep us updated on that supercharger. What kind of kit did you buy? How much PSI is it boosting you?