The older Ford GT with the the first 2 engine upgrades, racing exhaust, racing manifold. I also have racing air filter, computer upgrades, and high rpm supercharger. Amazing sound in cockpit view, even on my cheap sound bar. Gives me chills at high rpm.
Any of the quad-rotor Mazdas. 787B, LM55s, RX-Visions. The sound from inside the cockpit especially. GT Sport was an improvement over previous titles and GT7 is no different.
Scared the people in my house one day when I was playing GT Sport. Took the 787B to Monza for the Group 1 Cup race (the one without the first chicane; it was a decent race for grinding) and was on the chase cam. The volume on the TV was up high enough for my folks to hear it and wonder what the hell was up.