The G5 features an independent front suspension and a semi independent rear torsion bar. The only engine sold with the car so far is an I4 that makes a respectable 171 horsepower.
The G5 is only sold as a 2 door coupe in the United States, but a 4 door sedan version of the car is made and sold in Canada and Mexico, so it's probably only a matter of time before that version of this car makes it to the American market.
The transmission options on the G5 include a 5 speed manual and 4 speed automatic.
Aside from the base model, there is also a G5 GT sold in the United States. It has the more robust DOHC engine. It has an MP3 decoder and the first 500 came with a free XM satellite radio upgrade. The price on the GT is about $18,000, while the base runs about $15,000. Pontiac claims that they will not be making a supercharged version of the G5 GT, but Chevy makes one for the Cobalt SS so it's probably only a matter of time before that engine makes it to the market.
The G5 is too new to be showing up on the used car market, but you can buy them at a discount by looking on eBay.