Just completed my HU upgrade (for my 06 Civic EX sedan) using the Scosche replacement dash kit and I have to say that I am unimpressed. The color does not match very well (it's lighter than OEM) and the top right corner does not sit flush against the dash (about 1/8" off). It is not noticeable from the front seats but it should be a better fit than that.
For those considering this product, I would look to OEM or other companies.
As for the PAC steering wheel control unit, again, I am unimpressed. This is for my Alpine 9857 with a direct line in for the unit. It will work the volume and channel buttons but not the mode button. PAC tech support wanted me to wire it a little different but that did not work, so all I have is the volume and channel buttons functioning. Also, the response time has a little delay so I find myself pressing the buttons more than once almost every time to get the volume or channel changed. All in all, it's better than not having the steering wheel controls.
Wiring all of this was time consuming and difficult to say the least (6-7 hours min.). Finding a spot for the cross-overs was a challenge as the dash insides are tight. It was sure fun pushing the finished dash in, thinking I was done, and finding the back left speaker dead (a butt connector came loose) and having to reopen it all again.
As for the sound improvement (MTX 37x2 amp running Kappa components up front and the HU running Kappa 2 ways in the rear), it's massive over stock. Bass is a little lacking but easily fixed with a small sub. The Kappas are clear and clean as expected. Clarity and tightness was helped by adding eDead to the doors, rear deck, and floor (another time consuming pain in my a$$).
Total cost came to about $700 with the sound deadening, connectors, dash kit, 9857 HU with iPod connector, speakers, amp- most all eBay'd.
In the end, worth it.
Good luck.