The Sky, Solstice, and Opel GT use the Kappa platform architecture. Very nice structure. The central tunnel/side rail design is similar in design to the Corvette.
Some GM component sharing:
Rear axle and differential are from the Cadillac CTS
The Solstice's interior storage bin is from the Cadillac XLR
Passenger-side airbag, steering column, and exterior and interior door handles are from the Cobalt
The backup lights are from the GMT360 GMC Envoy
HVAC system/controls are from the Hummer H3
Fog lamps are from the Pontiac Grand Prix
The steering wheel is from the Pontiac Torrent
Ecotec engine (2.4L) is shared with the Saturn Ion, Pontiac G6, Chevrolet Cobalt, and Chevrolet HHR
Same manual transmission as the Hummer H3, GMC Canyon, and Chevrolet Colorado
Same automatic as the Cadillac CTS, STS, and SRX
Nice performance, however CRAPPY storage. About 1.2 cubic feet in the trunk, and zip in the cab.