Welcome to GenVibe Susan. I think I'll be able to offer you the BEST response since I own a 2009 G8 GT (titled in my name BUT it is the wife's car, whose name just happens to be Susan

). First bit of advise ..... KEEP the Vibe as it will cost you next to nothing to continue driving & maintaining it. It is already paid for and if you were to trade it in, the dealer won't give you "jack" for it

. Also depending on where you live, you'll want to park the G8 GT in the winter and drive your Vibe in it's place. Rear wheel drive, low profile tires, and all that power = sliding & dangerous driving in the snow. Our G8 Gt has never seen snow and with the optional 19" rims w/summer tires, it wouldn't even make it up our driveway one winter when I had to move it over one bay in our garage, with a little bit of snow on the driveway. Another thing is that all that aluminum under the car (engine, frame members, etc.) would get destroyed after driving it a few winters here in the midwest.
The G8 GT has many more blind spots and you sink down into the seats each time you get behind the wheel. I believe the car is something like 6" shorter in height if not more than the Vibe. I can easily wash the G8 GT getting full coverage and I'm a short 5'-8" whereas I have difficulty reaching the center roof areas when washing the Vibes

Fuel economy on the 6.0 litre engine isn't bad either. Full city 16-17 and full highway 24-26mpg. The acceleration will definitely throw you back into the seats if you're not used to a car with this much power

. My Susan loves that feature of this car.
I could go on & on here on mainly "positive" comments about the G8 GT but no time. The only big drawback is cargo carrying capacity in the G8 GT. They have the battery in the trunk (drivers side) as well as the Onstar & Sirius/Xm equipment ALL mounter under the rear deck, and it sometimes gets in the way when loading my hockey equipment (or any bulky objects). My hockey sticks need the fold down center arm rest down to fit them in the car. Rear seat legroom & comfort are incredible. I bet I have 12" of extra room from my knee to the back of the front seats

. This is a teenagers dream car if they were to use it for some serious "making out"

we're talking about lots of room back there!
Look into it BUT I'd keep the Vibe ...................................... Good luck
