I've been pleasantly surprised at the evolving note (voices, actually) of my 13 Boxster S. At about 40 thousand, a more resonant, deeper sound. I figured the motor had reached full maturity. Not so. At 60 thousand, there were more nuances, and more depth. By 80, even more so, with whirling, whirring, and zinging. Now, at 90+, the startup idle has a cavernous resonanance, like orchestral cellos and basses playing, along with a metallic, yet sinuous clatter and rasp. Amazing; dare I say "awesome."