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There's an alignment chart floating around this forum that shows the same spec's for the FE1, FE2 & FE3 suspensions. I believe the FE1 is the Base and the FE3 is the GS. The FE4(Z06) & FE5(ZR1) is different.
The FE3 is the old Z51 suspension. If you notice the Z06 and ZR1 have slightly different specs even though they are both wide bodies. You really need to check the latest Service Manuals that have GS specs to see what the settings for the GS are.
Interestingly, GM seems to not update the previous years' specs when new specs come out.
For example, when our dealer tech looks in the GM computer to check on "trim height" (ride height); the narrow body 2005 is different from the 2009 which is different from the 2012. But physically, the body and suspension are identical (if you have the same suspension).
My inside source tells me the 2009 numbers are for "settled after a thousand miles or so", the 2012 specs are for "new, coming off the production line". But you can't tell that either from the books.