mudgel
Why not download the 64 bit versions from your account. You have access to both the 32 and 64 bit versions of the Toontrack products.

I tried doing that and now Sonar freezes when I try to load SD2.

In general if a vendor makes a 64bit version of their product it should be used instead of the 32bit version in 64bit hosts.
 
In the case of Toontrack, their 32bit Superior Drummer 2 does not work in 64bit hosts. You must use the 64bit version of Superior Drummer 2 in 64bit hosts. Although to install the 64bit version, you must first install the 32bit version. Make sure SONAR is loading the correct version.