OE ZL1 wheels are possibly too wide to fit - not sure what the offset specs are, and they're like the stock SS wheels--quite pricey, though I can't provide PN's or price info.
http://www.chevrolet.com/camaro-zl1-sports-car.html?seo=ysm_|_GM+Chevy+Retention-X9223686_|_GI-RTN-Camaro+ZL1-BP-SN-Exact_|_Camaro+ZL1+HV_|_camaro%20zl1
"ZL1 offers two 20” wheel options. Both have 20” x 10” front and 20” x 11” rear sizes and are forged-aluminum, optimized for high strength and low mass. The standard wheel is a black 10-spoke — or opt for the polished 5-spoke."
Aftermarket knock-off wheels, such as shown below (20 x 8.5 - offset 35 front and 20 x 9.5 - offset 40) are more likely to fit, but there's no guarantee it won't be without some clearance issues (rear wheels). The stock SS wheel, 8.5 front - offset 48 and 9.0 rear - offset 57 are made to ensure NO body clearance issues arise.
A 9.5" rear wheel with +40mm offset will result in nearly a full inch of wheel further outboard from the stock rear wheel, so it may be necessary to roll the rear fender lip(s), depending on tire size and ride height.
ZR1 Camaro Wheels
Chevrolet - Camaro ZL1 Wheels
Not to mention that you would be able to buy 4 of these wheels for less than one stock ZL1 wheel--but you do get what you pay for! They're cast, not forged, and weigh significantly more than the OE wheels.
Does anyone know if the Camaro ZL1 or SS wheels are a direct replacement for the SS?
So, a proper response to your question would be...maybe, with an *asterisk* that wheel offset is going to be the determinant or detriment, depending on your viewpoint. Camaro SS wheels are 20x8 - 35 front and 20x9 - 40 rear, and many are being used on G8, which suggests they'll work on SS.
If you're looking to be different, I've had my eye on
these:
Fitment for G8 in this case is 19x8 - 45mm offset, but if you wanted 19x8.5, buy the BMW spec wheels (I used 2004 BMW M3 for reference), which are 19x8.5 - 40mm offset. I've not researched for a wider rear wheel with the proper offset, and it may not be available - the BMW selected shows 19x10 - 23mm offset, which won't work. A call to Tire Rack would be necessary to see what is available either larger or wider than the 19x8.5
(with a suitable offset).
The HLT low-pressure casting process results in a lighter but stronger wheel than standard gravity casting. The BMW wheel would only need a hub-centric ring for proper fit on the SS. As you can see, these wheels are not as inexpensive as others, but still not as much as the OE wheels.
another example--there are many