I got this info:
SONAR X2 Upgrades are available for download directly from Cakewalk. Choose from the products below and then select your qualifying upgrade option.
From this page:
http://www.store.cakewalk.com/b2cus/category.aspx?categoryID=9&cat=9 And when you click on Sonar Studio it brings you to this page:
http://www.store.cakewalk.com/b2cus/ProductInfo.aspx?productid=10-CXSR2.00-20E On that page it gives you two options:
Download for any SONAR (except LE) Customers $49
Download for any Registered Cakewalk Customers $75
Since you qualify as "Any Registered", you can upgrade right now for $75. Give em a call, and see what they tell you.
I am sure that the X2 Studio will install in it's own folder, leaving Guitar Trks still usable.
I have Guitar Rig 5 installed on my PC and I am able to use it in Sonar X2 with no problem. Did you upgrade GR5 to the full version? Or is that something that came with Gtr Trks? If it's not the full version and it's a version that came with Gtr Tks, then I am not sure. Maybe someone who did the same upgrade could chime in.