Does the amp have speaker level line inputs? If so it should be pretty easy. Don't forget to install a fuse inline near the battery for the power.

 

Email Kevin from Integral Audio and he'll explain what he did to me when I asked him about a Clubbie sound system. Depending on if you have the Harmon Kardon system or base makes a huge difference as to how easy this will be. On the Harmon system the amp and the speakers are your crutch, you can't just replace the speakers since the frequency is controlled by amp and would sound horrible. Need new amp and speakers in that case, i.e Soundstage Kit.

 

It's a really simple process to do. I've done it a couple of times on my own Mini's. One without Harmon Kardon and one with. Same with either and it helps with both! A lot....

You need a Line level input/output adapter

Open the back panel and find a set *left and right channels* of speaker outputs coming from the amp or any that are heading to a speaker and tap into those wires. Easier to do it in the rear of the car. You can find different crimp tools to just snap on to the right and left wires. Use a good double sided stick tape to secure it to the body. Then a set of RCA cables to plug from that output into the amp then amp to the speaker. Super easy.

I went the extra mile and ran a separate cable from the battery and as stated above by M.t.M, make sure you add a fuse not far from where you run the lead. You can also tap into the rear cigarette lighter spot for power which is really easy to do. Also a really good idea to use a 1 Farad capacitor so you won't have your lights dimming when your bumping along. You're welcome to send a pm and I'll give you a bit more information if you want. Here's my set up.

 

Did someone say Kevin?? Your timing is good, we're recently back as sponsors here (winding up to finally launch our SoundstageDSP™ kit for the 3rd gen MINIs...

OP, our MCWH-X9331 harness is designed to help you do exactly what you are trying to do. That is actually the harness from our original Soundstage™ kit for the 2nd gen MINI's, we make it available for the benefit of the DIY community. You can find it here: https://integralaudio.com/x9331-wiring-harness.html


MCWH-X9331-S MINI Cooper Stereo Wiring Harness

For anyone in the R55 crowd looking for a subwoofer, our Phantom™ subwoofer system for the Clubman is available again. It had been discontinued, but we were able to source the woofer for it again, so it's back! Integral Audio ® Phantom™ Subwoofer System for MINI Cooper Clubman: https://integralaudio.com/phantom-su...r-clubman.html

 

Amps are installed in the spare tire location

Looks messy here, but you cant tell anything is done the car.

System diagram layout.
I just installed a full system in my 2010 Clubman S. Below is my walkthrough on exactly how it did it.
My club man had the 10 speaker Harmon Kardon system. In this system the speakers are wired as follows from the factory:
1. Front right and left tweeters in a pillar and in parallel with the front left and right 3.5 midranges in the door
2. Front left and right woofers off their own channel on the amp
3. Rear left and right tweeters off their own separate channels
4. Rear 6x9 off their own separate channels

So in the end, even though its a 10 speaker system, the H/K amp has 8 output channels.

The stock H/K system has built-in equalization from the factory which boosts the front woofers at 70hz and cuts the rear woofers at 100hz.
The issue you are going to run into is either tapping in the front, gives you a boost at 70hz then rolls off on a steep angle, or the rear which rolls off on a 100hz on a steep angle.

For me, I was like you and didn't want to rid of the factory head unit as I liked the look. For me, I am an audiophile at the age of 22, I have installed several systems, never did a hack job, wires are hidden and the sound is so clear.

For me to integrate into the factory head unit I had to take a few steps, the factory amp is behind the rear right panel in the trunk. I went into that location and got to the stock amp. I spliced all the front channels using "9wire". Below is how my stereo is set up using the stock head unit.

1. 9wire off H/K amp into a JL Audio Fix 82. (Fix 82 removes all factory EQ and time correction and leaves you with a perfectly flat response, and you have the ability to tune the system with your laptop.
2. Fix 82 to RCA's inputs of Pioneer 8604 and Pioneer 8601 amps
3. Full alpine type r component speakers in the front and rear
4. Alpine Type R Sealed 10.

Total system RMS is 1,200 watts. Crystal Clear flat response.

 

Hey Energizer, thanks for the great posting! I'm well past 22 but am glad I can still learn a thing or two from the younger generation. I'm on a little different route though and bought a Helix Pro2 dsp to start and am now looking at 2, 5 channel amps. I'll post the system once im done. Thanks for sharing your work bro! You definitely rock! Pun intended!!
Peace