Change your dash speakers.. FX3 is about $100 per pair. RX47 hopefully about 100-110 if you share it with someone. This alone will be more than sufficient for most.
If you enjoy more bass and better surround, you can do what I did for my own car...
The wires connecting to the 4" rear parcel shelf can be tapped. The power is supplied directly from the EHU. Not from Amp1. The frequency from this output is full range. Meaning you get the highs and the lows. If you just replace the 4" with after market 6x9"s there will not be enough power to drive them without an extra amp. I already tried that with dismal results....
The wires are connected to a line out converter which will convert the signal from the wires to an RF output. This then can be connected to the amp to drive your speakers.
The advantage of tapping these wires instead of those from amp1 is that..
- It is easier
- You can still get the high frequencies
- You can still tune the front/rear fading volume from the head unit
The results is very impressive. Not to seem bragging but I set in a Saab 9-5 which had a 15K setup and really could not hear much significant difference.
Amp --- about $200+
Bass tube --- about $150+
6x9" --- about $100+
Line out converter -- about $100
Installation is actually quite easy...but of course i had the pros do it for me