This is what I have, a very nice camera with a user friendly interface. I can use the App on my phone to download videos off the camera, same goes with all WiFi BlackVue cameras with or without scree. I also bought from the website I am linking you to, their service is second to none.
http://www.in-car.com/vehicle-recorders/blackvue-dr750lw.php
With regards to installation, don't pay to have someone fit it. It can be a bit tricky feeding up into the headlining, few cuts later (who would have thought the edge of the headlining was razor sharp) and it was in. But, if you just go with the front facing then that won't matter, just a small run down to the glovebox. Whereabouts are you based? If you were local I would be happy to help. I have the Front & Rear because I had someone hit me on the motorway last year, who did a runner. Luckily someone called in with the registration and we were able to get about 10 seconds of footage from the useless motorway CCTV, to prove his dangerous driving. If I had this camera, it would have been a clear cut case in court.
I have hard wired mine, using a fuse tap (will come back to this) and the beauty of it is, it is permanent live now so it records while parked and cuts out of the voltage drops below a set level. For when I park at the airport for example, I can just swap the fuses over in the glovebox and it is then only only with the ignition to save battery and ensure that I see what it's being driven like at the P&R (not left the S3 at the airport and won't be, I will get a lift).
This is what you need, in conjunction with in my case the Blackvue hard wiring kit, which is a 12V socket with 2 bare cable ends to terminate.
http://www.ebay.co.uk/itm/2pc-Add-A...106702?hash=item23624d940e:g:3HQAAOSw3ydV5lbw
Simply crimp the red cable into the fuse tap, terminate the negative on one of the bolts beside the glovebox which can be seen by clipping off the side panel. Look at your manual. pick a fuse which you think will be either switched live (easy ones to find) or permanent live (I can tell you what I found if need be). Remove the existing fuse, plug into the fuse tap and push the fuse tap in.. easy as that, two fuses in one socket.
If you take your time, it will take about a hour for the front facing and probably around 2-3 for the rear, if you do it properly like I did you should feed the cable for the rear camera through the rubber cover between the body and tailgate, then both boot panels off to feed the cable in (pain in the a***).