I WILL BE INSTALLING A PIONEER D3 IN MY '06 CIVIC. DO I NEED THIS PART IF I WANT STEERING WHEEL CONTROL?

Yes.

You lose your steering wheel controls when you remove factory-installed cd/radio player.

I lost mine in 07 camry, but I don't think its a big deal. Volume knob is very easily accessible from the drivers' seat.

I WILL BE INSTALLING A PIONEER D3 IN MY '06 CIVIC. DO I NEED THIS PART IF I WANT STEERING WHEEL CONTROL?

yes i did a pioneer radio the 5900 into an 06 civic with the pac... it sucked... but maybe its cuz i havent done pac in a while cuz we dont carry them anymore

it works perfectly, just make sure you connect the 5100 ohm resistor like indicated to do by the instructions. all the factory buttons work and work as they are labeled.