Looking on that first link....there's an 01 for sale. 4999999 yen...which comes out to 53000$. Plus importing fees and whatnot, might as well get an r35 here.
I'm saying 10v of money man is the same as 10v of lady gaga. There is no difference if the amp can get the current it needs it will see 10v all the time.
Meh...the lower the voltage the more current its gonna pull. Producing more heat. Heat which over an extended amount of time can kill components in the amp. 10v for a few seconds is just fine....now over three or four songs....bad.