Here's the TSB, I've searched alot and everyone seems to say the 97' and up condenser fits and made the biggest difference. I'm going to replace that first and go from there.
Overheating/Air Conditioning Shuts off in High Heat
Article No. 96-25-12
^ AIR CONDITIONING - AIR CONDITIONING SHUTS OFF IN HIGH AMBIENT TEMPERATURES AND VEHICLE MAY OVERHEAT - 4.6L AND GT OR COBRA
^ COOLING SYSTEM - OVERHEATING AND/OR VEHICLE GOING INTO THERMO PROTECTION MODE - VEHICLES WITH 4.6L ENGINE AND GT OR COBRA
FORD: 1996 MUSTANG
ISSUE: In severe operating environments (ambient temperatures above 38°C/100°F and/or extended high engine rpms) some vehicles may experience engine overheating and/or enter into the thermo protection mode. In thermo protection mode, the A/C system will shut off accompanied by a reduction in engine power. This may be caused by insufficient cooling from the cooling system in these types of environments.
ACTION: Install a severe duty Cooling System Kit. The kit will increase the vehicle's cooling system capacity to operate more efficiently in severe conditions. Refer to the following text for additional information.
The Cooling System Kit will include a larger radiator, larger cooling fan, a revised A/C condenser and all necessary hardware.
NOTE : THIS TSB ARTICLE PRIMARILY AFFECTS THE WARM SOUTHERN UNITED STATES (ALABAMA, ARIZONA, CALIFORNIA, COLORADO, FLORIDA, GEORGIA, LOUISIANA, NEVADA, NEW MEXICO, OKLAHOMA, SOUTH CAROLINA, TEXAS AND UTAH).
Cooling System Kit Part Number:
OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage
OPERATION DESCRIPTION TIME
962512A Install Modification Kit 4.1 Hrs.
DEALER CODING CONDITION BASIC PART NO. CODE 8005 11
OASIS CODES: 402000, 609000, 609500, 609600, 614000, 614500, 614600