The front speakers (I believe) stock are 5.25", and the rears are 4". The fronts can take a 6.5", but you need to watch for the length from front to back of magnet as it could run into the window track. The rears with slight, if any, modification can take a 5.25". With much modification it can take a 6" - 6.25".

The way I understand it, the amp is rated at a certain number of watts... you then divide it up by the number of channels (1, 2, 4), although, you will see almost all 2 or 4 channel amps out there state something like "400w amplifier, 4 channels, 75w per channel"... it doesn't add up, but that's how most do it. When you bridge, you use a positive (+) from one channel and a negative (-) from the other... 2 output terminals, both of which have signal on them.



You do this to increase the power to the sub... meaning, on a 2 channel, 4 ohm, 250w amp, instead of pushing 75w - 100w divided by 2 channels, I am now pushing 200w - 250w by 1 mono 4 ohm channel. You can also bridge into a 2 ohm or 8 ohm signal, but only recommended for speakers that take that load.

As for the front and rear being 2 or 3 way speakers and throwing of the "sound stage"... well, truth be told, yes, it probably will. Now, whether that really matters to you, it is UP to you. Car manufacturers always push the "6 speaker stereo option" thingy, even though they are out of phase. None of the speakers are equidistant from the listeners ears, and the waves are bombarding them from all around the car. The perfect setup would be you, right in the middle of the VX, and the front speakers aiming in the exact same direction at you, thereby sound like it is in "stereo"... like you cannot tell there is sound just coming from each side but from the sides, middle, and rear.

This won't happen as you need to drive your VX, so you have to be on one side of the car. Many believe you only need some good front speakers and good positioning of the speakers to have the best audio setup. I think it's true, but I also wanted some bass... so a sub can be brought in to bring in the bass without effecting the phasing as much as rear speakers would.