Vert vs Hard Top???
 

With the below mods will my heavy azzzzz 03 gt vert keep up with a stock hard top 99-04 gt?

K&N FIPK,
Magnaflow Cat Back
Steeda Tri-Ax
Steeda Underdrive Pulleys
Diablo Predator

YES. It should PASS a STOCK Hardtop with those mods.

Thanks. I was just curious cause don't the 99-04 verts weigh about 300-400 more than hardtops?

Yes sir. I believe thats correct

Bit over 300#
 

300# and a bit more. Aerodynamic penalty, too.

Drop the top and you have a more equal situation on twisty roads, with the lower center of gravity (offset by the greater weight, of course).

tripleblack

You are forgetting chassis stiffness. The coupe would be able handle better than a convertible unless the convertible has significant chassis stiffening.

If you are looking for a corner carver a convertible isnt the best starting point, you are at a weight penalty and a stiffness penalty.

Also in alot of cases the suspension on the convertibles are not as stiff because most convertible owners want a softer, cruiser ride. I am not sure about the 99-04 Mustang but I know the 05 GT vert has a softer suspension.

Why They're Heavy
 

Late model converttibles are heavy because they have lots of stiffening added to them at the factory. This is not to imply that they are as stiff as the coupes (although the 05's are much closer than prior models) - just be aware that all convertibles have subframe connectors and welded-in cross-plating (about 150# worth) that coupes do without. Older model mustang convertibles lacked this added work, and their flexible flyer handling showed it!

The idea that a convertible that would struggle to keep up with a coupe in a straight line will tighten the gap on a road course is not new. Because of all the chassis stiffening additions (most of them located low down on the unibody) and the fact that the coupe's roof is both heavy and the highest portion of the car means that the convertible's center of gravity is lower. As I said, this advantage is offset by the added weight, yielding a more level playing field but no net advantage for the convertible on a really twisty course.