I test drove both cars expecting that the mach 1 will be slightly better than the GTO since it is a special edition. I wasn't looking at both car's hp because the GTO clearly wins. But in terms of driving experience and comfort. The mustang definitely loses in this department. First off the Mustang felt so cramp inside and everything felt cheap. I was hoping that it would be slightly better than a regular GT, but I guess I was wrong. The shifter was also kind of weird, I was never really sure what gear I was in and it felt notchy. While it felt smaller inside, the Mach 1 felt like I was driving a huge car. Probably due to the huge shaker hood. The gto was a luxury car compared to the mustang. Everything felt more solid and rigid. There were no rattles, and felt like there wouldnt be any rattles coming soon. The interior was warm and the pieces felt tightly together. The shifter, however, felt like rubber. It did not feel solid like a smooth shifting honda transmission. The seats were also great compared to the Mustang's bench like cafeteria seats. Power wise, I wouldn't really be able to compare because I did not want to push it. I was kind of annoyed with the GTO's skip shift feature because I kept shifting to 2nd and the car bogged down.