I too switched out the stock speakers in the front. The task of taking the skin off the doors to get to the speaker is very simple. Nothing can go wrong. One hint I may add is when you take the bolt off the centre trim piece of the door (the one where your hand goes to open and close the door), the whole unit pivots on the front edge closest to the front of the car. Take a small screwdriver on the rear section of the piece and lift it up gently. Disconnect the power window wiring and start popping the skin away from the door.
I also installed Alpine speakers and the sound is incredible. I did however notice I need to increase the volume of the stereo to get the speakers to drive a sweet sound.
Both doors with soldering of the new wires and installation took about an hour. This mod is worth the time. Now I need some aftermarket tweeters to complete the mod. I have some Infiniti speakers for the rear, but this mod may have to happen in the Spring. Hockey season is a killer for me and the kids.