From what I've read it is only about 40 pound difference. There is a brace behind the back seat (prevents folddown) and 2 braces underneath floorpan to trunkpan that had to come off for springs.
Depends a lot on options but my stripped 2008 V6 Deluxe Convertible (not the premium) weights 3334. Automatic probably adds weight too, the top probably is a wash since it is vinyl or fabric.
__________________ 2008 V6 Deluxe Convertible, Torch Red/Parchment top and interior, 5-speed manual, Exterior Sport Appearance Package
Mods:
K&N 63 Aircharger Cold Air Intake, JBA Evol Axle-Back Exhaust, Hurst Competition/Plus Short Throw Shifter,
Ford Racing Performance Parts front strut brace,
Ford Racing Performance Parts rear lowering springs,
GT Vert rear anti-sway bar | 
V6 coupe Versa V6 Vert 
Even though the car has extra braces in the rear they don't weigh anything ,, ?
