Aren't we all? Yeah, I love the Cobra's as much as the next guy, but I'd have to say the 280hp number is more credible based on the trap speed M/T got out of it.
Here are the figures
0-60 5.2
1/4m 13.8@102.0mph.
We all know those guys couldn't drive a Mustang through the McDonald's drive thru, but the trap speed should be higher than 102 with your numbers. Guess that car is already on it's way to being shrouded in mystery like the Shelby Cobra's.
I would disagree with the idea the hyper pistons caused a performance drop. If anything hyper pistons would be a performance enhancement. They are lighter than their forged counterparts, with less weight, the engine should make more hp. The technical reason Ford gave for the decrease in performance from the '92 models to the '93 models was a new rating system. From best to average motor ratings. That's more likely a front for the power they couldn't pull out of the 5.0's they wanted to see. In truth no 5.0's were released with dyno numbers after 1987 models, and the drop in output from 225 to 205 is more likely related to the MAF system, de-tuned computers, cam revisions, and some other minor changes. 1993 models pretty much got the worst of the worst for computers too.