switched or solid live wires to tap into etc. Is this the case with the 156?
If it is anything like the GT, yes!
Is it an ISO harness for the mik9100? If so, it is kind of plug and play. You will have a yellow iso to back of stereo with, potentially, a yellow cable coming out of the back of it (think it's the yellow ISO - defo a yellow wire) that's the "mute" for the "phone" just mutes the stereo and "Phone" appears on the stereo display. patch the mute cable on the kit into this wire if you want the display on the stereo to show "phone".
Live and switched - I fitted a Motorola tk30 and tapped into the cig lighter switched live using bullet terminals. hope that helps some. there is apparently a live cable on the ISO terminals in back of stereo but it couldn't work for me so had to change to the cig lighter.