He didn't like the car. Saying a 700HP 911 or Vette feels faster. Of course they have more available torque. The supercharged mustang feels' NA as far as power delivery is concerned and it has to be revved out. If you turbo a mustang it will be faster or as fast feeling as a 911 or vette. Luckily my GT doesn't grind but not a great transmission. I debated getting a camaro simply because they come with a tremec just don't like the way the camaro looks (if it had an interior that lookedlike from this decade I would have considered it. The best manual car I have ever driven has to be a s2000 transmission.If you feather less, the grinding won't be as bad. If you practically start dumping the clutch every time you shift, you'll barely notice it. I think the grinding comes down to build quality. There are plenty of 18/19s which don't grind regardless of how much you feather. Also, the GT350 has a twin disk clutch and I've never seen anyone mention anything about grinding when shifting.
Just watch the video below at 5:30.