Re: started tear down of the 01 motor
I've had 2-3 different LS with leather, come to think of it.. I don't believe Regal comes cloth. Century is cloth only. The reality is ... all the options were pretty standard. So on a regal, options would be
Dual auto climate vs Dual manual climate
Sunroof or not
Wheels, Brushed, Chrome and I think you could order steels with caps
GS charged vs LS not charged
Body on the GS was almost always two tone, LS was almost always single. You could order the two or single. Largely though, if you see a two tone, it's GS.
There was a spoiler add on that dealers sold, it was not a option that could be ordered TMK.
Autotinting exterior mirrors were an option. All exteriors are heated, but the autotinting was an option.
I believe you could also order the DIC in the LS, GS came standard with it.
The controls for dic/etc always had a blank button, there was not a feature for it.
Perf/not shifter. Depended on year IIRC. Might have been optionable