You don't need to wire up the speakers to the wires "correctly". Connecting the positive wire to the positive speaker terminal and vice versa with the negatives won't necessarily ensure the best sound, so the best idea is to remember which way you're connecting up the speakers (write it down), and then play with different combinations of wiring until you get the best sound.
I thought that putting the +ve and -ve the wrong way round, would make the cone move the wrong direction, I'm pretty sure connecting them up correctly gives the best sound, otherwise why would they bother displaying +ve and -ve on speakers?
Things sound good when the sound is in phase at your ear, not when it leaves the speaker - people make the fundamentally wrong assumption that wiring the speakers in electrical phase (moving the same direction at the same time) means that the sound is in phase, which it's not (your ear would have to be on top of all of your speakers at the same time for this to be the case).. what's important is that the sound is in phase when it reaches your ear, which is effected by the distance the speakers are from your ear. If they're all the same distance, wiring in electrical phase will be correct, but this isn't the case in 99.9% of car installs. Play with the polarities until you get the best sound.
@ MulletBoy, much appreciated mate, that makes sense now thanks.
@ smiddlewood, I wasn't necessarily challenging the info given, just trying to understand it, and giving what I thought was correct. How does my number of posts on this particular forum indicate my knowlegde of ICE etc. seeing as I have only owned my Rover a month, so am new to the site.
Incidentally, if you want to get fairly technical, phase is unimportant above about 2KHz, so you can wire up your tweeters (assuming you have a component set) in any combination you like - swapping wires will make no difference to the sound you hear (you won't hear much, if any sound from tweeters below 2k in most cases).
For midbass phase is VERY important, and slightly less so for low midrange, so these are the key speakers to play around with phase on.