I’m going to upgrade the sound system for my ’04 coupe. I’m confused about a couple of probably really simple issues, so for you pros reading this, please bear with me. And I’ve spent a lot of time reading searching this forum and reading old threads…I think I”m more confused than when I started.

My requirements are pretty simple: I want a head unit with USB input for iPod touch / iPhone 3GS, and I want to manage the bass output to the door speakers and the behind-the-seat speakers. I’m old; I don’t want my bass output to shake the cars next to me -- I just want accurate, high-fidelity sound across the Hz.

I’ve picked the new(ish) Sony MEX3700U, with front iPod input, front AUX input, and Bluetooth A2DP. With that many options, If I can’t get music out of my iPhone and into the car, then I have a personal problem.

I’ll order from Crutchfield. So here’s where I start to get confused:

Q1. Does Crutchfield understand the Crossfire -- will they send me the right wiring harness and instructions? I thought I read on this forum that the Crutchfield experts had the wrong diagrams when it came to the Crossfire….

If it looks easy I may give try the installation myself. I’ve read that some HUs can be swapped with the factory unit wire-for-wire, plug ’n play. I doubt that this is true with the Sony unit. If so I’ll take it to a local installer. So that’s the second question:

Q2. Are there any special instructions to give to the local installer? Any gotchas about the way the Crossfire is wired up that would surprise an installer? Should he by-pass the factory amp and wire the speakers to the Sony’s amplified connection (17 watts RMS x 4 channels)? Or should he wire the factory amp to the Sony’s 3-pair pre-amp outs? (front, rear, and subwoofer (non-fading)) Or other?

Finally, I’ve wanted to kill the mid-bass madness in the door speakers since I bought the car. Since I’ve never mastered the Pelked1 capacitor mod…

Q3. Should I ask the local installer to do it for me, or is there a better way (e.g. use the pre-amp outs as mentioned above)?

I really appreciate any answers, opinions or experiences…