Not sure about alot of the changes to the CD4E after or during the 2000 build year, but it's possible that one of the differences could be the location of the VSS. IIRC, in the later models they changed the VSS and the location.
Not sure about much else that they might have changed after that. Good question, just one that haven't really researched alot.
I am searching the Borg Warner site right now to see what I can find out, because after a quick search over at Bulk Part I found that there are some differences in the 2001 and 2003 rebuild kits. What they are I don't know, but I am going to find out.
{EDIT}
Only differences I can find are the forward, low/reverse friction plates. The Forward friction plate has Radial Grooves as of 2001 and the Low/Reverse friction plate has Double Parallel Grooves as of the same year.
Other than that... that is all I can find. No other aftermarket or OEM provider has much info out there.
