I've had good experiences with FORD extended warranties. I just took my car to the dealer, and they handled all the contacts with the warranty division and repaired my vehicles. My particular experience was very good, as they covered several high price repairs that far exceeded the price of the warranties. I've had 3 warranties on three different vehicles. The last one was the EXTRACARE warranty(3 year 36,000), that I purchased from the dealer; after getting a price from lombardfordwarrantys.com. The dealer agreed to reduce their price to meet that of Lombard Ford. Lombard often run promotions that reduce the price of the warranties.
If you look at the PDF of the warranty coverage's, the circles for all the plan except the premium care are half-filled for the engine and transmission.
If I was purchasing a GT500 with a turbo charger, I would try my best to get the premium care warranty. I wouldn't want to take the risk of any repairs being in the half-circle that is not covered by the warranty.
Only you can determine how much risk you are willing to take, and how much money you have at your disposal. I've been there, and wish you the best in your decision making process.