Performance
Regarding horsepower, the STS-V packs quite a wallop and will knock the Cadillac STS down a few rungs. On the other hand, note that high horsepower engines often command higher insurance premiums.
With that kind of horsepower, both the STS and the Cadillac STS-V are genuine speedsters.
Handling
With their similar turning circles, the Cadillac STS and the Cadillac STS-V quite certainly handle roughly the same into and out of tight spots.
Drivetrain
The STS's engine is significantly smaller than the STS-V's. Remember that a smaller engine usually has to work a little harder; on the other hand, smaller engines are often cheaper to fix.
The Cadillac STS could learn a lesson or two from the Cadillac STS-V when it comes to torque.
Utility
Neither the Cadillac STS nor the Cadillac STS-V has a marked advantage in terms of seating capacity.
Convenience
You will have to visit your friendly gas station more often with the STS-V than with the Cadillac STS.
Dimensions
The Cadillac STS-V is significantly heavier than the Cadillac STS.
The STS and the STS-V compete for the same parking spaces.
Cost
When it comes to fuel economy, the STS has the STS-V beat.
The Cadillac STS will save you money at the pump compared to the Cadillac STS-V.
The Cadillac STS-V is tremendously more expensive than the STS regarding MSRP.
The Cadillac STS will save you a lots_of_money at the pump every year compared to the Cadillac STS-V.
Warranty
The STS-V and the Cadillac STS have the same basic warranty.