ohh no.. the old "better wires will sound better line"... for speakers... I would NEVER believe that .. damn you can use a strait coat hanger for the + and - and I bet you 1000$ you will not hear the dif.. lol

The interior side of a door is the same environment as the interior of the car. In fact, the trunk is often a worse environment - it's not heated well and has large metal panels with no vapor barrier on them.

If done correctly, most people will have no problems with a crossover in a door.

hack!!!!!

Yes,
But if the trunk is safe enough for the electronic internal parts of an amplifier(s), then it should be safe enough for cross-overs, unless of course your trunk lid leaks.

I don't think it's a "better wire" argument as much as it is a bigger wire argument. My factory wires are about 20 gauge. I'm running 200WRMS to each of my components. I used 16 Gauge wire to cut down on power loss due to the wires heating up too quickly (one guy told me for that power I should use 14awg - but I think that's just over kill for a 6 foot run). If my car would have come with 16AWG run to the doors, I would have used the existing wire.

Also, I believe that car doors are designed to allow water to flow through them.
If the manufacturer would make the window seal waterproof, I think we would have a very difficult time rolling windows up and down (or we would need much more powerful motors for power-windows to operate smoothly). Likewise, making lock and handles waterproof is not worth the time and energy. Just make sure the inside of the door channels the water well and directs back outside of the car and everyone is happy.

Wiring size can play a huge roll if it's too small. Like running 100+Wrms through factory 20 guage wiring will be audible in that your midbass will have very little controll as the added resistance in the wiring would be sapping power bigtime. 16 guage is pretty much adequate for everything but subs. where Regardless of power I always go minimum 12 guage.

I used 2 runs of 16 for my one sub. . . but its only getting 500RMS (and I was too cheap to get different wire for my sub)

Mine have been in my door for about a year now... Yes because im lazy, but theres been no problem what so so ever. So as it is for me atleast.... if theres no problem, why fix it?

Why don't you open up your door and have a look at them and see what kind of results you have?