I have the P3 installed on my 1M and love it...especially monitoring my air intake temps as I drive on the road...and I like how it integrates so well into the dash.
Install was about an hour total but I had to run a boost line to my engine...you won't be doing that.
But the best thing is that it closes up my OBDII port so some a-hole trying to steal my car via the handheld key coder will have a harder time freeing up my OBD port
That being said, you can't beat $25 for a bluetooth transmitter and smartphone app...to each his own as I don't own a smartphone...
And the 0-60 is fun...real time capture...good luck with your project.