Capacity is the same. But the GT tanks (as well as 99/01 Cobras and Mach's) come with a single pump set up. And that pump is in a canister. Some pumps can drain that canister. The 03/04 cobra tank is set for twin pumps. It has baffling for those pumps. If you need a tank you can look at Glenn's Performance as well. I installed a set up on a buddies 97 GT and it was clean.