I did this with my Valentine 1 the other day and figured I'd post a brief how to. I have an '11 S GT but most this should be the same on any second gen.
Tools
-T-25 Torx screwdriver
-Flat tip screwdriver
First remove overhead counsel
Remove two(2) T-25 trox screws from sunglass holder
Remove map light covers with flat tip
Now it should pull down.
There are three(3) connetors on it remove them by pushing in on the tabs
Two(2) on right side
One(1) on left
You should see a black box with another connection on the left side bolted to the roof
Remove the tape from the wire to expose the wires. The pink wire will give you power only when the car is on(I'm pretty sure it's for the sunroof)
For the ground the only place I could find that was easily accessed was where the torx screw that holds the counsel up
Run the wire for the the detector so it comes out from the front of the haedliner. Tuck the wires and reverse the steps to replace counsel
Tools
-T-25 Torx screwdriver
-Flat tip screwdriver
First remove overhead counsel
Remove two(2) T-25 trox screws from sunglass holder

Remove map light covers with flat tip

Now it should pull down.
There are three(3) connetors on it remove them by pushing in on the tabs

Two(2) on right side

One(1) on left

You should see a black box with another connection on the left side bolted to the roof

Remove the tape from the wire to expose the wires. The pink wire will give you power only when the car is on(I'm pretty sure it's for the sunroof)
For the ground the only place I could find that was easily accessed was where the torx screw that holds the counsel up

Run the wire for the the detector so it comes out from the front of the haedliner. Tuck the wires and reverse the steps to replace counsel