Okay, this might be a dumb question, but can I just unplug the X950BH and plug in the W8500NEX?   Are the harnesses the same?  Or do I have to get a new harness and whip out the soldering iron?   It's my wife's 2001 Boxster, so there aren't any steering wheel controls to worry about.

Thanks!

I just installed a 8200nex into my car. I was somewhat surprised to see that the Pioneer "power" plug is the same 2x8 pin rectangular plug that I'm used to from 15 year old single DIN headunits. 

So the W8500NEX still uses this plug, but there are other options as well. 

To be clear, the "power plug" serves many functions. First, it supplies power to the unit - ground wire, constant 12v power (for preserving settings and memory), switched 12v power (so the unit turns on/off when you turn your key), and illumination setting (so the display brightness matches your interior brightness setting). Those are the 4 main power wires, and the rest of the wires in the 16pin plug are for speaker signals, remote amp turn-on, and etc. 
In the newer models, the power plug also has wires for the vehicle speed signal (VSS), reverse signal, and parking brake signal. The VSS is for GPS function, which the 8500nex has, but your other model may not. The reverse signal is for back-up camera option, which your older model may not have supported. And then the parking brake wire is for confirming the vehicle is parked when you want to watch video content (DVD, HDMI input, etc). 

So, in short, the plug from your old unit will fit into the new one, but you may have to add a few wires or tweak some things.

3 hours ago, Stomachbuzz said:

I just installed a 8200nex into my car. I was somewhat surprised to see that the Pioneer "power" plug is the same 2x8 pin rectangular plug that I'm used to from 15 year old single DIN headunits. 

So the W8500NEX still uses this plug, but there are other options as well. 

To be clear, the "power plug" serves many functions. First, it supplies power to the unit - ground wire, constant 12v power (for preserving settings and memory), switched 12v power (so the unit turns on/off when you turn your key), and illumination setting (so the display brightness matches your interior brightness setting). Those are the 4 main power wires, and the rest of the wires in the 16pin plug are for speaker signals, remote amp turn-on, and etc. 
In the newer models, the power plug also has wires for the vehicle speed signal (VSS), reverse signal, and parking brake signal. The VSS is for GPS function, which the 8500nex has, but your other model may not. The reverse signal is for back-up camera option, which your older model may not have supported. And then the parking brake wire is for confirming the vehicle is parked when you want to watch video content (DVD, HDMI input, etc). 

So, in short, the plug from your old unit will fit into the new one, but you may have to add a few wires or tweak some things.

Thanks for the response!   The X950BH  has similar Nav features, just as the unit it replaced (we originally had the AVIC-Z1 in there), so it used the illumination wire, speed wire, reverse wire, etc..  Sounds promising.  I can just pull the unit when the time comes, and if the power plug is the same, and the wires line up, then it sounds like I have a shot at this being EASY!  That'd be nice for a change. 

Yep. I've gained some wisdom from my younger days and searched for a Pioneer to Toyota harness in advance. $16 for a pre-made harness! Easy is nice. 
Although I could have popped it in just on the black plug, I got curious and started poking around my 8200NEX. This thing is crazy! Even though I never would have plopped down the cash for all the extra feature this thing has when buying new, I figured I might as well take advantage of the knick-knacks while I have my dash taken apart. 

Again, I'm not the type of person who set out with the desire to output video from my phone onto my headunit screen, but I found that I can buy an MHL adapter for $20 to feed HDMI into the NEX for perfect screen mirroring. That was pretty hard to ignore. 

Interesting!  So how old is your X950BH?

I found that the black power/speaker plug from my AVIC-D3 (2008 era) does not plug into my new Pioneer AVIC-8500NEX.   It’s very close, but I couldn’t get it to go and thought best not to force it.

Would be so much easier if it did!!!!