Installing Photosynth as a 3rd party app

[DaFeros]

Hello everyone. My 920 has starting to give signs of wear, as its microphone works irregularly. As I've been told, when I send it to repair, I'll receive it clean from any data. Which would be a problem if i didn't get the 805a8011 error when trying to access the store or connect to Xbox.
From what I've read, the only solution to this would be to hard reset it, losing all data anyways. Photos can be backed up, music I can get it back no problem. The problem are apps, which have to be reinstalled. One in particular, Photosynth, has been pulled off the store not too long ago. Now it's impossible for me to get it the legitimate way after a reset.
I found an alternative method which is registering as a developer and loading the .xap file into the phone. As I've never done something like this, I wanted to understand the risks of doing so and if I would be violating any terms of use of the phone or similar by Microsoft

The app would be downloaded from here: < Moderator edit - link removed >

 

[Pete]

As far as I'm aware, you can only load xap files that you have downloaded from the store using the same Microsoft Account that's on the phone.

Finding another xap file on another site is technically piracy (even if the app is free). You're better off finding another app that does the same thing in the marketplace.

 

[DaFeros]

Sorry for evading the link fillter, I thought I was causing no damage.
Yes, I guess it's not right to install an app like that, but I fail to see the harm on doing so in this case, as the app is not only unsupported but also unpublished, as Microsoft apparently gave up on it. I've already looked for an alternative, but if our platform wasn't lacking so much on them, I wouldn't be so reluctant on losing this app. The only app that seemed similar is Google Photo Sphere, and we already know how much Google loves WP