World Class and non-World Class versions of the T5 - How to tell them apart.
The Countershaft Bearing Cup: With the bell housing removed, look at the front of the T5 case. There is a distinct difference in the appearance of the countershaft bearing cup when you compare a non-WC and WC T5. See the photos below. Test your knowledge on the 3rd photo.
There are differences on the inside too. The non-WC have brass blockers (also called synchros). - Please see photos.
The inside of a non-WC and a WC T5 look very similar. However, if you see brass synchros, then you will immediately know that it's a non-WC.