How does that saying go? An amplifier is only as good as its power supply.
I
for one can sure as hell hear a difference between the "cheap" amps and
"costly" amps as I have stated below. If Mark thinks that all amps have
the
same exact power supplies in them, then that works out great for him, at
least
he can get away with running cheap amps while we have to pay a lot more to
make our ears just as happy.

No Mark doesn't think that, nor did Mark or anyone else in this thread say
that. Pug needs to create an argument that he can win, so he came up with
that one.

I have owned enough different amps in my time
(cheap and costly ones) to know that all amps don't yield the same sound
quality. Here's a page about power supplies and sound quality, it's
written
around home amplifiers, but the same rules apply to car amps as well.
http://www.tnt-audio.com/clinica/ssps1_e.html

If you want references (you know, credible ones - references that have been
published either as books or as articles in reputable journals; not
websites), I'll be more than happy to supply them.