As much as I like a clean sound... Over doing it in a car is pretty much worthless... Sure go with the best that you can, but I've never understood people spending $10k on a system and then trying to justify their 'investment' by saying it's because of SQ. Bull, in a car there are too many variables.
Anywho, enough with the rant (which wasn't directed to you btw). If you want oldschool, wait for Zed Audio's new amp line up. He supposed to be releasing a 6ch amp that will obviously have his legendary touch. 6 x 150W is what it's supposed to have.
Just a suggestion
Unless you really want to be period correct, in which case take a look on ebay and see what you can find, but be prepaird to spend a lot of money on the good old stuff.