I can promise, yes, this is a guarantee, that the difference in sound between speakers would be a much bigger difference than any potential difference in sound between two quality headunits.
Promise. Guarantee. No two ways about it.
I never said run out and get a Rampage headunit. But the difference in sound between a quality, affordable headunit and a big expensive headunit like the Mac will not be greater than the difference in sound between speakers. Not to mention the added processing that most headunits have will more than make up for any (potentially) inherent sound differences between something like a Mac and an Eclipse 8053 (for example).
It's okay though...you're old school, and have the "old school" philosphy that things like the headunit and amplifiers will make or break a system, so those need to be the biggest and best you can afford. When, in fact, there are better places to allocate the money towards //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif//content.invisioncic.com/y282845/emoticons/tongue.gif.6130eb82179565f6db8d26d6001dcd24.gif