install was pretty easy, thought you do need to drill some new holes in the side bracket from the old head unit. as far as wiring it is all plug and play (except for the reverse camera). It is a pretty good head unit but it does have some issues, it is not refined as say a pioneer or some big brand. To replace the crappy music app and to get the steering wheel controls to work in all apps you need to install a custom ROM, this is pretty straight forward, thought to the tech illiterate people this could be daunting. If there was not a custom rom, I think the device would be average.
Radio reception sucks in the D40, some cars have FM amp in the antenna line and some have in the head unit, i assume the d40 is in the head unit. So you will want to get one of those. I would get a propper one and not an inline one. This will be about $30 us and will require wiring in (just for power).
Bluetooth audio sucks, not for music but for the person on the other end of the phone, they can hear a lot of static (and your voice), this is electrical interferece on the mic line, there is a well known mod you can do but it requires opening the unit and desoldering/soldering. looks pretty simple, i will probably have a crack at it at some point. but once again daunting.
only other neg i have is it will only sleep for 2 hrs, then it will require a cold boot when you turn it one, this takes about 30 seconds. Which sucks when you just want to get in the car and use it. The camera will work straight away though. I am working on getting around this, either through software or through wiring a relaying in to my central locking to boot it. Hopfuly software will get around it.