I think it may fit...
Hello,
Your MSP has the Kenwood head unit in the top DIN-size location and there's another DIN-size space just below, with a little cover.
Taking out this bottom plastic box you'll have space for another DIN-size head unit, but the thing is very likely you'll need to move the Kenwood MP3 head unit from the top location to the bottom one, so you will still have access to its controls whenever the XAV-7W's screen is fully open...
For doing this, a trim kit or custom adapter may be necessary if the XAV-7W's plastic trim doesn't cover completely the gaps that may end around this piece's faceplate.
I am not completely sure if an installation kit is mandatory but that shouldn't cost so much anyway...
Connections wise, you can feed Kenwood's audio (RCA preouts) signals into the AUX1 input of the XAV-7W, and (I imagine you'll have one) your separate DVD or video source audio signal into its AUX2 connections. That way you'll be able to control all incoming sounds from the XAV-7W as a master.
The only thing is the Subwoofer connection. I am not sure how it's connected to the head unit but I imagine the Kenwood's subwoofer RCA outputs go to a dedicated subwoofer amplifier powering the under-rear-deck 10" unit.
This can still be the same, just now the subwoofer amp will be connected to the XAV-7W's subwoofer output, so you can also have bass from your video programs. In this scenario, the front and rear speakers will need to be changed from the Kenwood head unit to the XAV-7W's speaker outputs so you can also hear the video source audio signals through your speakers...
I hope all this theory may bring some light to your questions.
Good luck,
FEDE
