Wheels are a good investment for speed. The general rule is the more aero, the better. Since you are on the coast side of Fl, hills aren't an issue. Where hills and climbing are involved, that's where the lighter weight of 303's over 404's come into play. But without hills, the aero benefits of 404's are important.

Bike weight is one of the most over rated things. Unless you are talking about extremes (25 lbs vs 16 lbs), bike weight is incidental. Wheel weight on hills does made a little difference, but that's it.

So consider aero wheels. There are lots to chose from. Also make sure your position on the bike is right. That are wheels are your best means of adding speed