Rub what in? Your inability to understand or address what I've been saying a million times between the 2 threads about this topic? It has already been substantiated that there is no difference between GR-2 and Excel-G. Christ, I'm the one who even quoted where it clearly stated this off KYB's own website on this very thread, even bolding the specific text where it states this.
http://www.grandprixforums.net/kyb-e...tml#post564900
NO one has argued that the lines themselves are different at this point. What we're trying to figure out now, as matt5112 stated, is how much of a difference is there between the regular GR-2/Excel-G replacements for the w-bodies, and the ones specifically for MC/Impalas with the FE4 suspension (which is a completely separate part #).
"boooooooooooooooooooo yaaaaaaaaaaaa!!!!!!!!!!!!!!!!!!"
What was that again Ridin ON Chrome?
Sorry, just had to rub it in since you didn't seem to be understanding what the discussion is about at this point.
THREE part #s for KYB w-body replacements. One most likely being the original GR-2 # we've been using all these years, then the Excel-G # that will be an identical replacement for the GR-2 # we've been using all these years (eventually rendering the original GR-2 # obsolete), and then a (2nd) Excel-G # specific ONLY to FE4 suspension equipped w-bodies. Once again, the real question now is what all is different on the FE4 specific struts. It may not be much, but I'd be curious to know exactly what it is, especially since the OP said the tech that started this whole discussion said it has a .4" lowered ride height.
If you'd still take the AGX' over the lowered ride height, that's your business. I'd rather have the stress of the Vogtland's .9" lowered height on our struts chopped almost in half with a .4" lowered ride height strut to minimize the wear as much as possible.
That is most likely for liability purposes. Since your car didn't come with FE4 suspension from the factory, they are not going to list a part specifically designed for that suspension as a suitable replacement for your application. This happens all the time for parts that people know are interchangeable, but are not listed that way. For example, we know the variable rate springs on the other w-bodies will fit on our GPs, but they're not listed as options for our cars when you look up springs on most sites. But since we know they fit, we can just look them up as Regal springs and purchase them that way. Only thing with these struts are we don't know yet 100% if there will be any fitment issues or not. I doubt it, but until someone tries it, we can't say for sure.