Even 200 pounds lighter plus Alpha's superior chassis dynamics would make the 6th gen a vastly better car.

Completely agree! It should make for a much better driver's car.

That would put the 6th gen SS at 3,650 to 3,700 +. Still a bit on the heavy side in my opinion, but I think that Cadillac has some equipment and sound insulation that the Camaros may not get, so you can maybe subtract some weight from there.

I still think if they put the 6th gen on the same chasis as ATS we could see the SS come in at the 3,550 to 3,650 range, but if they put it on the longer version I don't think it will hit that weight.

Can't wait to find out :)

Something to keep in mind from a handling standpoint besides weight, is weight:wheel ratio. 1LE for example - ~3850lbs., but it has 10" and 11" wheels - total weight divided by total wheel width is 91-92lbs per in.
Current ATS has 8's and 9's - to have the same lbs/in, the car would have to weigh 3130lbs.
A real win would be decreasing weight (especially front weight), decreasing overall size (including wheelbase), maintaining or increasing power, and not hamstringing it with narrow wheels. Good width wheels are a key element of the current Camaro having fared so well in its various handling-based matchups; if the 6th Gen loses 300lbs. but gets the ATS wheel widths, it will probably not possess the handling limits of the 1LE+ class 5th Gens.

How many of you guys have even sat in an ATS? It's a verrrrrry small car compared to the Camaro.

Just make sure you realize that with the lower weight would come Cruze sized Camaro.

Also Ford's use of aluminium is nothing special. GM was way ahead of Ford in full size pickup weight. Ford had the catching up to do. And aluminium panels are more expensive to replace and repair. Insurance costs "may" be impacted by this choice. The market will tell, but GM had aluminium panels on many vehicles and removed them (Liftgates for example) because the cost benefit wasn't there.