Fixed that for you. Yes I agree pony cars are supposed to be smaller and lighter. But Mustangs really aren't smaller and lighter anymore.
Uh, though fairly true, check out the 1971-73 Mustangs. Those things were OBESE!
Unless Chrysler "quality" has improved 500% or more, good luck on "quality". Their products kept me making money and supporting my family with one income. Our city had a "vanpool" program where they bought nothing but Chrysler minivans and some SUVs. Our shop saw them every week with a variety of problems. Having a pattern failure issue is one thing, but having failures in many of it's systems is clearly a sign of poor implementation in manufacturing. When Daimler-Benz bought them out, I heard it was to obtain their computer tech (their engine controls were really great, it's just that the support components like sensors and actuators were the downfall). Once they got that, they sold it. Needless to say, the city eventually dumped them all and I see some Ford and Toyota SUVs now.
I had a '71 Mach 1 and yes, it was the largest (dimension-wise) Mustang up to that point, but it only weighed 3200 lbs. My S550 GT weighs 3700 lbs. However, overall exterior dimensions aren't much different and we were able to put 3 people in the back seat (someone small was able to sit on the "hump" in the middle).The 2015+ Mustang is larger and heavier than the 1971-73.
Actually, the '71-'73 may have "looked" that way, but it's only an inch longer and and inch taller than the current S550; the S550 is just under an inch wider so for all practical purposes, they're identical overall, except that the S550 is 500 lbs. heavier (heavier engine and trans compared to the 302-2V and C4 automatic in the '71-'73).
My '12 and '13 Jeep Wranglers (both bought new) were the last Chrysler products I'm likely to own. Problem after problem, and neither was abused. The '12 I had less than a year, so many issues I thought it was possessed. Ordered the '13 hoping the '12 was a fluke, but dumped it at 60K after it became obvious that I'd have an expensive repair annually out of warranty. Shame, since I loved them.
This was my experience with the Challenger during a test drive, very boatish. The Mustang was much tighter and, no offense, the Camaro 1LE handled way way better than either of them.