In in a mk4 mate.
I take it by properly u mean dynamatting?
Just had a go at getting the amp cable through today after looking at many guides, and still can get the buggar through
yeah the power cable is a bit of a PITA on mk 4's. behind the glovebox is the best place IIRC. Thats why you want a MK3, there is a huge grommet big enough to fit a drainpipe in on these badboys
by properly I mean fitting the speakers to metal of the door, rather than just the door pockets. This gives them a ridged baffle to play from, try installing a speaker in a cardboard box and compare it to a wooden box, you should hear a difference.
Also, I don't know if you have ever taken a doorcard off a car door but the part where the speaker plays into is full of holes from the inner skin back into the doorcard, this means these holes also get to the outside world ( kind of) as the doorcards are not sealed airtight to the door. Sealing these holes up with either some kind of sound deadening or preferably something more solid would also go a long way to increasing the front speakers effectiveness. The idea is to make the door more like a box, which is what you want.
sound deadening the whole door is also a worthwhile step, just be careful not to block up any drain holes in the bottom of the door. There are better/more cost effective methods than dynamat out there.