I can only speak for the 2010-2014 gen from experience, but I think his views are a little skewed...
Technically, the Mustang GT (5.0L V8 420hp/390tq) competes with the Challenger RT (5.7L V8 375hp/410tq). The 15+ plus generation makes it a little harder to match them up since the Challenger doesn't have a 4 cylinder offering. So speaking of the RT, the GT will drag it all over town. The challenger is a boat, and every car guy knows it.
The SRT 392 is in a category of it's own. The 6.2L brings the challenger up to par with the GT, albeit a little quicker, but it needed an extra 65hp to do so. As far as low end grunt, while I feel he is a little right, but a larger motor is typically more torque-y. A simple $300-500 tune session on a GT with stock everything livens it up. From the factory I imagine it is the way it is to appease the masses. I don't know how he drives, but the car pulls in all gears. It takes time to learn where the power is and what gear to be in.
Not to mention you could pick up a GT premium for a sticker of ~$38,000. The scat pack starts at $43,000, or the standard SRT 392 goes for $50,000.
Don't get me wrong, I thought about grabbing the challenger because it seems more practical with it's size, but in reality for the extra 12k, alot could be done with the GT to edge it far beyond the SRT 392.
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