[QUOTE=nick325xit 5spd;1225545]The reason to use AVIN is as follows:
1) Replaces a failing MID or head unit. (My MID's display was ruined.)
2) Sounds VASTLY better than the original head unit.
3) Added functionality such as CarPlay may be desirable.
4) If you DO NOT have DSP, the installation is pretty much direct drop in.
/QUOTE]
So an AVANT4 is almost plug and play?
The CD/Bluetooth wire option increased sound quality. The OEM wiring changes are noticeable. The plug in Bluetooth adapter through radio frequencies doesn't compare. Next year, I'll go for an upgrade to use all the steering wheel buttons.