Without getting into brand specifics, if you want to skip the sub stage, you're going to want dedicated mid-bass drivers- otherwise, you're asking too much of the mid-range drivers. You'll want 6 channels of amplification. with the HU you picked out, you don't need the amps to do anything but amplify, so your choices are wide-open. DO NOT use the factory speaker wires. They won't be able to carry the current an amplified signal will give you. You can get better amps than the Rockford for $400. Search product reviews and such on here, you'll find a ton of good info on specifics. Speaker selections are pretty subjective so I won't even steer you in a direction.

 

I can't help much except to say that I'll bet $100 bucks that the factory speaker wire will not hold you back at all. I personally would upgrade, because you have to wire an amp anyway, but factory speaker wire probably isn't going to cause a problem at all.

I say 'probably' because I don't know what size wire is there, but in my opinion people tend to exaggerate the necessity for fat speaker wire.

 

From just some calculations I just ran into an 8 ohm speaker...the stock wire which I think is 22 AWG (1.614 ohms/100ft) should be good for about 20W RMS. Those focals have a 92 db (2.8V/1m) sensitivity. At 20W you'd be blaring those speakers.

Now for the back speakers, you guys say I should go with some good mid-bass drivers. Normally bass'y speakers have a much lower sensitivity. Which means to get the same SPL's, I'm going to need to push more power into them. I may want to rewire the rear drivers with something like 16 AWG wire (.4016 ohms/100ft) or 18 AWG wire (.6385 ohms/ 100ft).

Also, if I'm just using the rears for bass, I may want to just wire them in parallel, run it mono off the HU, and have them share a channel on the amp. That would likely lower them to a 2 ohm impedence circuit thereby reducing the current necessary to drive it and also reducing the size of the necessary speaker wire.


So to recap...

Leave the stock wiring in the front... use 16-18 AWG for the rear mid-bass speakers.

Now the next question is, if the front speakers aren't going to take too much power, is the amplifier in the CDA-9887 any good? I'm probably only going to be pushing real world 5-15W/ channel to my speakers. I think that amp is good for 25W/channel....if they're clean real world watts.

 

Why don't you want a sub? Even a thin one or a 10" ?
It would be easier to achieve a good sound quality.
Just a 4 channel amp(look at the Sundowns 100.4) powering a good set of comps and a small sub. And you're good with your 9887!!!
Good luck for your choice, but re-consider the sub option please: midbass in the rear OH NO!!!

 

I don't have the 2001 GTI locations memorized... can you put a 4" in the dash? If so you can go with a 3-way kit and get a dedicated midbass in the door.

Avoid R speakers entirely and spend the money on the fronts. Dynes in the front with a 2-channel, and no rear, would be better than a 4-channel and rears, with lesser up front.

 

The GTI has space for a 6.5" front and rear and 2" (??) tweets front and rear.

The fronts you have to be pretty picky on the speaker depth, but I hear the back you can get pretty deep speakers.

If I can get the front to sound really nice and clean, I don't care that much about the back. And I really value my trunk space. My car is my income. I do mobile IT work and I'm hauling stuff all over all the time. I need every cubic inch back there and I need to be able to fold the seats flat and have the entire back used for storage sometimes.

With that said, what do you guys think of:

Rears: Vifa P17WJ00 or Tang Band W6-1721
Front: Focal 165A1
Amplification: Alpine PDX 4.150
HU: Alpine CDR-9887
Sound Deadening: Dampifier Pro on interior surface of front doors and back panels or spray on Spectrum on same areas. (The spectrum would be nice because of the significant reduction in weight)

 

Phase 1 has been purchased:

# Pending Install - $0 - Wiring Harness: Crutchfield PN # 120701784
# Pending Install - $346 - Head unit: Alpine CDA-9887
# Pending Install - $163.95 - HD Radio : ALPINE TUA-T550HD
# Pending Install - $140.95 - Front Components: Focal 165A1
# Pending Install - $370 - Alpine 150.4 Amplifier
# Pending Install - $14.96 - Alpine KCE-422 iPod Cable

I still don't know what speakers to put in the back. I think that's going to depend on what size I can get in there. I posted on vwvortex if anyone knew maximum depths, but no one was very helpful. I'll take pictures and measurements sometime soon and get back to you guys.

How large a fuse do you think I should get for that amp? And what gauge wiring should I run to the amp?