Rack & Pinion - correct application

[67goat]

Just wondering if anyone knows the difference between the GM part numbers listed for the Rack & Pinions with variable assist (NV8) which SSEi models came with from 00-03.

So far per a couple GM part webpages I visited, seems like my '01 (and most '00-'02 models for that matter) reference GM part # 26098782, along with a few other GM part #'s cross reference for the same application.

When browsing Rock Auto's webpage there are even more GM part #'s referenced for 00-03 models which is when I became confused (some exclusive to U.S. cars, others both U.S. and Canada) and there is one option that stands by itself (GM part # 19320497) that has the same NV8 option but does not cross-apply with the other part #'s I found. Further, looks like '03 models came with either part #19169233 or 19153563 depending on the engine VIN #.

Bottom line, though from the exterior it appears most these are interchangeable, does anyone know if there is an internal difference between the bunch? Seemingly # 26098782 would work for my '01, but before I purchase a replacement, was wondering why GM would replace or supersede seemingly the same application with different part #'s. Was it a design improvement? Especially the '03 part numbers seems to stand alone from '00-'02.