I happen to know just a little about the particulars of these Mustangs and you are mistaken in your assesment of the relative performance qualities of this car versus the Porsches and BMW's (I added the Bimmer reference as I am quite well informed about those cars also.)

The Mustang Grand Am Cup car, depending upon the race and weight penalties applied to the car (Let alone the initial weight of the car-which is very, very heavy.) had a power to weight ratio that was just about equal to slightly better than the Porsches, slightly less than the BMW but probably better torque to weight ratios than either car. (But not much.)

The car's strength was, actually in it's superior cornering ability to the other cars. I have a good amount of segment times from various tracks for most of the cars running and the Mustang showed it's best in medium to higher speed corners, where it was simply slightly quicker than the competition. As a small increase in corner exit speed translates into a huge benefit on the straightaway the Mustang just looked like it had more power because it would seem to pull away on the straights, which it did, but do to corner exit speeds.

The car had problems with braking, due to excessive weight, a funky brake booster curve from the factory (Too much assist to the rear-which cooked the rear brakes all of the time.)

Also look at the drivers of the quick Mustangs-Scott Maxwell, Gunnar Jeanette, David Empringham. Note exactly slow guys! And the team (MTC) was very well prepped. Now I will admit that the total combination of cars, drivers, team, etc was a bit much compared to the competition, save Tom Milner, his Bimmers and Bill Auberlein.

I know it seems hard to believe that a McPherson strutted, stick axle pony car should be a better handling car than the likes of a Porsche or Bimmer but again there are reasons for it. The Porsche has very bad rear suspension geometry when lowering the car, which limits the total rear grip of the car. So the Porsches have to run a stiiffer rear spring setup than optimal to limit rear suspension travel, and thus stay in the good range of their geometry.

Also the Mustang geometry was modified by some of the best guys in the business. I am talking about Jay O'Connell, Dave Williams, Micheal Gutilla, etc. Now these names may mean little to most people but Micheal is one of the original creators of the ADAMS vehicle dynamics package, which is the industry standard, Dave Williams is the guy who came up with active suspension for Lotus, is the originator of 4 post rig testing and Jay is Ford's best vehicle dynamicist-period. Add the work done on the dampers by these guys and you have a package that is very tough to beat. I doubt any other car in the series has been on the 4 post damper rig at all, let alone the number of times the Mustang went on it-all to optimize the mechanical grip of the car.

Now was this a case of using a howitzer to kill a mouse? Perhaps but Ford wanted to showcase the Mustang and sell racecars and we went in to win-period.

In a related case-look at the Panoz Esperante GT-LM car. We (MTC) got our hands on it this winter, developed the car using our expertise and it is now the fastest GT2 car on the ALMS circuit. (Right now.) The car was quickest at Sebring testing, Sebring qualifying and won the race. Now this is a Ford powered car-same 5 liter modular engine (Yes-built differently) that is beating the Porches, BMW's and heavens-even the new 430 GT2 car. (Though they are going to be quick as the season goes on.)

And yes, I am biased-I am the technical director for MTC. But I carry some credentials also:

1.) Past Technical director for Panoz/ Elan Technologies
2.) Designer of the BMW LMP cars that won LeMans in 1999
3.) Contracted by Lola to help design their current LMP cars.
4.) Etc, etc, etc.

And finally, these cars are, for racing-quite a bargain. You can pick up one from the factory for about $120 grand. Try that for a Porsche or BMW cup car new from factory.