I had to wait three months for Lenovo to replace my X1 Extreme's motherboard because switching to discreet graphics to install Linux bricked it.
Here where I live they would have to refund you the machine, if they weren't capable to repair it within 30 days (while under warranty, which I assume X1 Extreme was). The only manufacturer, whose service is able to achieve 30 days here is Apple ;).
With Lenovo, and previously IBM, I've had experience to have issues fixed NBD, even when I was retail customer.
I just got it back and as much as I want to use it I'm trying to return it still...
I love those guys.