A few pictures to show the progress are attached.
The new IAM, or really a Pioneer DEH-X9600BT that I bought for my old VW Jetta, which then moved into my Volvo 850, and now installed in my V50 when I scrapped the 850. It originally comes with a detachable face plate with the controls for anti-theft purposes, but I modified that and soldered some 8″ leads between the face plate and the main unit, making it somewhat modular. I did that so I could have the head unit leaning against the side of the center console in the passenger footwell and have the face plate in front of the gear shifter.
All the speaker wires meet at the IAM in a V50 with the ‘Basic’ audio package (This is for Europe, I guess the worst package available to Americans is the ‘Performance’). The amp is built into the IAM, and sounds like something close to 4x10W rms, if that. I cut the wires about 3 inches from the plug that goes into the IAM, and soldered my speaker wires from the amp in the trunk to the OEM wires. I decided to do it here rather than at each door because it’s a lot easier and makes for only one point of ‘break-in’. In case I ever need to bring it back to OEM, I can quickly solder the wires back together, but I do plan to drive this car until the day it’s ready for the scrap yard.
The bundle of wires from the trunk waiting to be cut to length and mated with the OEM speaker wires, not shown are the 3 pairs of thick RCA cables that I ran along the right hand side of the car.
The Alpine tweeter that I had to make a hole for in the OEM position. The ‘Basic’ sound package does not include tweeters, but the rear door cards are prepared for them, unlike the front doors. I suppose I could have tried to source some OEM covers for tweeters, but even second hand parts cost an arm and a leg here in Denmark and I don’t think it looks too shabby like this anyway.
All speaker wires cut to length, soldered, heatshrink-wrapped and cloth-taped just for extra security. The OEM wires are 17 AWG (1 square mm), I think, and I used 14 AWG (2.5 square mm) wires from the amp up to here, above the glove compartment. Relatively thin wires, but then again, I’m only feeding around 30-40 watts into each speaker.
The cables are neatly tucked up over the glove compartment and out of the way.
The new IAM 
in place. The CD player is no longer usable although it works, but I had to run the wires for the control interface through the CD slot. It lines up with the CD slot in the V50 trim, so I can run the wires through that later when I go about making it look a little nicer.
And this is where the biggest compromise enters the picture. Because the ICM is so monstrous large, especially above the LCD display, I just can’t make the Pioneer face plate sit flush with it as I had originally envisioned I’d do. Perhaps I could, if I cut in the waterfall trim, but that would leave an inch wide gap between the Pioneer controls and the ICM which would look just as hideous. Anyway, I’m prepared to live with this because the sound from this blew me away on the hour long test drive I went out on after this.
For now, it is only attached to the trim with 3M VHB doublesided foam adhesive. I’m going to try to 3D print a new trim piece I can slot the Pioneer face plate into with some PETG 120, which should be stable up to 120C/248F, but it remains to be seen if it actually is. If not, I might make one out of resin instead.
So, how do you think it turned out? Please disregard the missing trim around the ICM, it will be installed with the trim I’m making for the Pioneer controller.
On the hour long test drive I went on, so I could both hear how it sounded and charge the battery a bit, I was completely blown away by the sound compared to the Basic audio package. Some songs that used to sound like the singer was mumbling now sounds almost clear, and no matter if it was Guns’n’Roses, choral music or Pet Shop Boys, it all sounded great. In my opinion well worth the time and effort I’ve spent on it so far. Now I just need to get the LIN bus sorted….