Hello! It's been a long while from the last time I've messed around with xboxs so I'll need some help here. I have a xbox with a Xecuter3 in it and have two unmodded xbox 1s that I would like to install xbmc on them. What is the easyest way to do this? Thanks for all the help!

You could use your chipped Xbox to put a hacked game save onto a memory card and then use that with an exploitable game to soft mod your stock consoles. That's kind of about it in terms of initially hacking your stock consoles. After they're hacked and you have their EEPROMs, then you can use your chipped Xbox to prep larger hard drives.

Edit: I suppose one other thing you can do is temporarily transplant the chip to your other consoles and set up the soft mod files on them before removing the chip.

Bit late in the day for this now but I've hotswapped with Xboxes before.
Unplug the DVD lead from the stock one and boot up a modded one with a boot disc with FTP support, or maybe a file manager.
Once booted, swap the IDE cables so the modchipped cable goes to the stock HDD. You can now FTP onto the stock HDD. File manager seems a bit hit 'n' miss but that is to be expected.
I can't recommend the practice when there are better alternative methods.

Obviously it's not time saving if you don't have both the case tops off