Never compare a front wheel drive sedan with rear wheel drivers. They're in a different league. At any track or on the street the G6 will get spanked. My GT can hold it's own, don't get me wrong, but it's in a different size, and weight class when viewed to rear wheel drive Mustang, Charger, Camaro and even Genesis Coupe!
It would be appropriate to compare (and attempt to drag) a Ford Fusion V6, as it is not only front wheel drive, but has a smaller V6 with similar HP until recently when it was bumped from 200 to 240hp. Same with the previous Honda Accord.
The newer rear wheel drivers for 2011 will leave even the quickest G6 GTP V6 in the dust. RWD+300+hp+similar if not lighter weight and better balance and driving dynamics over a FWD G6= G6 will lose, every time no matter how skilled the driver thinks he/she is.
I owned a '91 LX 5.0 Hatchback and without a doubt, it's paltry 225hp could move. As mentioned above, the hard part was getting it planted to go fast in a straight line. At 110K miles my rear axle was toast, and I upgraded it to a 4.10posi and with that alone even my 'modern' G6 with 200hp or so wouldn't even come close to standing a fighting chance. The only downside is my old Stang was a terrible winter driver, which is why I ultimately ended up trading it in and went back to front wheel drive. Now that I bought a four wheeler, it ticks me off that I sold it years ago as it was a fine machine of its time.
'11 Ram SXT 4x4 quad cab - 5.7L V8; 75,500kms
'06 Pontiac G6 GT - 3.5L V6; 113,000kms
'12 Chrysler 200 - 3.6L V6; 58,000kms