Utility
Drivers with frequent kid-duty might favor the BMW 328 over the Porsche Cayman.
Performance
Regarding horsepower, the Porsche packs quite a punch and will knock the BMW 328 down a few rungs. On the other hand, keep in mind that high horsepower engines often command higher insurance premiums.
Dimensions
The BMW 328 is tremendously heavier than the Porsche Cayman.
The 328's tank is almost the same size as the Porsche Cayman's, though the Porsche Cayman's is a tad bigger.
The Porsche and the BMW 328 compete for the same parking spaces.
The Porsche's shorter wheelbase will likely give a more agile feel in daily traffic. On the other hand, the BMW is likely to have a smoother, more stable ride.
Cost
The destination charge is a standard charge for transporting the vehicle from its point of origin to the dealer. The BMW 328 is considerably cheaper to get to the dealership than the Porsche Cayman.
The BMW 328 is tremendously less expensive than the Porsche in terms of MSRP.
Handling
With their comparable turning radii, the BMW 328 and the Porsche Cayman most certainly handle roughly the same into and out of tight spots.
Drivetrain
The 328's engine isn't much larger than the Porsche Cayman's.
Torque is roughly equivalent to acceleration, and in this respect, the Porsche Cayman isn't much more powerful than the 328.
Warranty
The Porsche Cayman and the BMW 328 have the same basic warranty.