[c5 rv]

I'd look for a certified pre-owned unit. Cliff Notes of the years:

04 - 05: Wide doorsills can make entry and exit more difficult. Pants legs will often get dirty.
04 - 06: Interior has the same styling as the original CTS.
06 - current: Narrow doorsills and power rear liftgate.
07 - current: Restyled interior. However, some folks complain of sun reflections on the AC vents.

The SRX is a good dog car assuming your dog can jump into the rear hatch. (Buy the rear bumper protector to cover the top of the bumper.) I have the GM parts soft cargo barrier that uses factory mounting points behind the back (middle) seat. It goes up and down in a couple minutes and keeps a dog confined to the back. I'd also skip the 3rd row seat in lieu of the cargo management system. The GM parts cargo mat (rubber waffle type) is also a good addition.

As for engines, I've always said the V6 is OK for RWD, but the V8 is better for AWD. Your opinion may differ.

SRX drawbacks: The car has spent more time at the dealership than any vehicle I've owned in the past 20 years. There have been too many rattles and front suspension problems. Also, if you carry a dog in the rear cargo area, there are no opening windows, even vents. Dogs love to sniff the air go by.

The best dog vehicles I've owned are fullsize extended cab GM pickups. (The GM extended cab trucks have more rear seat room.) The rear seat folds up for larger dogs. For smaller dogs, a seat cover is useful. The trucks also have swing-out vent windows that dogs love.

My wife can no longer transfer up into a fullsize truck from her wheelchair. I picked up an 02 Dodge Dakota RWD extended cab. Our late dog loved to ride back there. Since there were no rear doors, the dog jumped into the front seat and (usually) went between the seats into the back.