Ummmm, thanks for the lesson…. “dude”
Now let me teach you one. The term is known as Parasitic “DRAG”, not loss and refers to resistance created by one of two forces…. One is the general size and shape of the object in question. Those with many protrusions will have a higher drag than "clean" designs. Another is the friction between the wind and the surfaces themselves. Regardless, neither one has anything to do with what’s being discussed here, since they are barely noticeable at these low vehicle speeds. Here's a bit of a reference to help you along.
http://www.madsci.org/posts/archives/sep99/936163217.Eg.r.html
Now that that’s out of the way, where have you found a stock fully loaded late model SN-95 GT that weighs only 3000lbs? Even most of the old Fox bodies weighed more than that. Realistically, there’s only about a 200-250lb or so difference between that an ’05 GT and an ’04…..not 500lbs like you claim.
Forgetting what you learned out of a physics test book for a moment, it’s entirely possible to get a 4000lb car down the track to the tune of 12.3 with less than 425rwhp. Yes, vehicle weight does have an effect on acceleration, but so does weight distribution and the vehicles ability to transfer it. The
suspension type/setting has a considerable amount to do with it, where the ’05 excels compared to that of the ’04 in both. There are several T-Bird Cougar owners such as my self who are doing it with far less that 425rwhp. As a matter of fact, an acquaintance of mine runs consistent 12.7’s and went best of 12.4X with as little as 330rwhp in his 3900lb (with him in it) T-Bird. I’m not really sure where you’re getting your math and reasoning from here (the new GT makes 300hp @ the crank minus an automatic (71.4hp) before it ever makes it through the drive train), So basically, you’re already knocking almost 25% of it’s horsepower off, before it even runs though the transmission, but I’ll let you in on a little secret here….the transmission is part of a vehicle drive train. And not all drive train loss is rated the same, considering the loss becomes less apparent on higher horsepower level outputs, than lower level. It’s not a strait cut 15%-20% (or in your reasoning, nearly 25%) no matter what! Now….are you starting to get the picture?
And….I have no idea where your header argument is from, but feel free to run with it anyway.