Hi,

I recently bought a MTX 502 Thunder Amp and it's built like a tank and is
quite hefty. It works great with my 12" sub. My (4) 6 x 9 speakers are
powered by a Kenwood Excelon 4-channel X-614 amp. The MTX is only a two
channel amp but weighs quite a bit more then the 4 channel Kenwood. This
leads me to believe that the MTX probably has larger capacitors and
Torodials.

No. More like larger heat sinks.

I was thinking of selling the Kenwood and replacing it with a
MTX 4-channel amp. I'm wondering if anyone has done a comparison of car
amps and if there is a big difference in sound quality from one
manufacturer's amps to another ? Please refrain from posting if you're in
the camp that they all sound the same............

In other words, "engineers please don't respond". Gotcha.