installed double din head unit

[ballcrusher]

Just installed my new head unit Pioneer AVH-P4200DVD 7" double din at a bargain price 2nd hand and to my surprise the amount of functions its got has made the stock speakers sound really good lol but at some point im going to do a full speaker upgrade with a stealth sub box with a decent amp but not sure what component to go with but i noticed there are empty speaker vents in the middle of both doors so don't no if the last owner has taken them out but advice on what to replace the stock speakers👍 also looking for a pair of head rests as I'm putting 7" monitors in both of  them as got 2 sets of Kenwood LZ-701W - LCD 7"monitors that will get installed after Christmas but please don't comment about the surround plastic as it was like that when I got the unit lol

[The Red Warrior]

I've recently upgraded my front door speakers and went with Morel Virtus 3 way component speakers being driven by a Morel 4.440 amp. I'm really liking them.
The vacant speaker location is for cars that have the 10 speaker system (as mine does) and the additional speaker attaches to the back of the door card.
If you do replace your speakers then you can install a speaker in this location too if you get 3 way component speakers.

[The Red Warrior]

No, you can't just add the speaker in by itself. You would need to use the crossovers  and speakers from a car that uses 3 speakers in each front door so that the correct frequencies go to the correct speakers.

As for your speaker issue, you may have some broken wires or broken insulation of your door wiring loom where it passes through the rubber boot between your door hinges. I had this problem myself recently.
Not a specially difficult job to check, just time consuming. I was able to do it easily though as I already had the door card and door skin off. You can see my photos of the wiring in my posts in the 'what did you do to your Mk5 today ' thread a few ago.
To remove the door card you need a plastic trim removal toll and T20 & T30 torx keys. For the door skin it's just the two torx keys.