i did mine recently, i upgraded to alpine speakers, best way to make sure you use correct + & - terminals is to look at the original speaker connectors, they only fit one way and have it stamped on them, just write down the colour of the wires on your car, some can be different! once your happy cut the old terminals off and crimp new ones on, the rears are exactly the same except you need to wire the tweeter to the live on your new conector aswell to power it, it took me around an hour to do and it now sounds a lot better from standard without any butchery involved!