@Stefos1 there is no m18 R2, yet. There are two versions for the R1 though with options for Intel or AMD.

I'd expect an R2 once the next generation CPU's and GPU's are available for laptops but that won't be for some time.

There was the M18x R1 and M18x R2 but these were released back in 2011 and 2012. 

It can be confusing if you haven't followed the product lines as they have been released over the years. See the link below which will help you out. 

https://www.dell.com/community/Alienware/Alienware-Laptops-naming-confusion/m-p/7594920#M29652