I agree many people have unrealistic auto performance expectations, but I think the point is that to have the option of a 5.4L in a GT would be great. I think jlisle01 would accept the fact you had to pay more for a 5.4L option over a 4.6L in the GT. The GTO had a nice LS2 in it, and its 400hp offering didn't cost anywhere near $41K either.
Also I agree that badging shouldn't really mean all that much. A Mustang GT with a N/A 5.4L by any other name would smell just as sweet. Though the name BOSS or Mach 1 could command some extra money due to its exclusivity and name recognition. However, the days of picking from a large selection of engines in a single model type is long gone. So I guess it is all a moot point anyway.
I also think the original point of the thread expresses a valid concern. I would guess that a lighter N/A 5.4L mustang would be a really low 13 second or high 12 second car. From a marketing stand point that is really close to the GT500.
No where in a paid advertisement by Ford are they going to tell potential GT500 customers to swap the pulley, adjust the factory tune, or open the intake for extra performance. Even though that kind of thing happens all the time, I don't think a company like Ford will openly market a vehicle based on its aftermarket potential. That would be like openly admitting their product can't stand alone and needs the aftermarket support. Is this true? No...but the masses are fickle, including the masses that can afford over $40K for a car. So Ford has to market the GT500 as it is stock with the intent of it remaining stock. To further illustrate my point, Ford offers an array of performance packages for the GT (drag pack, handling pack, etc.) to cater to the likes of the aftermarket crowd, but you don't see that anywhere in their television or standard magazine ads (excluding the aftermarket specific magazines).
Thus marketing a low to mid $30K Mustang SE and a low to mid $40K GT500 may prove challenging if they have similar or very close STOCK performance numbers. Since Ford has to market both vehicles as they come STOCK.
I think what we may see is a special edition released after the run of the GT500 is over. That way they aren't directly competing with each other. Again the special edition mustang is still just rumor anyway.....