I just purchased the Modifry DCI Wired Harness for an Alpine but i didnt purchase the PnP Harness because they didnt have it in stock. Do i need anything else to complete my install? Do i need to buy the s2000 stereo harness?

 

you'll need a Honda stereo harness - they are readily available, but many
of them don't have the s2000-specific dash switch wires (there are two
extra wires - one for the mute, and one for all the other controls).
It is possible to move unused wires within the connector to those positions,
but Modifry sells a non-PnP harness that has the proper wires, so he may
be able to ship that one with your DCI. After that you just splice the
Alpine harness (which should have come with your headunit) to the Honda
adapter harness and DCI harness.

 

If you can, I'd recommend waiting to get a PnP. I have one on my Alpine and it made the install super-easy, just plugging together some wires. JMO