Cost
The destination charge is a standard charge for transporting the vehicle from its point of origin to the dealer. The BMW is considerably cheaper to get to the dealership than the Boxster.
Regarding MSRP, the Porsche costs tremendously less than the BMW 650.
Utility
The BMW 650 will most definitely prove more practical than the Porsche Boxster for those of you with frequent child-cargo.
Comfort
While the front cabin in the Porsche Boxster offers a bit more head room than the BMW 650, there honestly isn't much of a difference.
Dimensions
The 650 is tremendously more bulky than the Porsche Boxster.
The Porsche Boxster's tank is about the same size as the BMW 650's, though the BMW 650's is somewhat larger.
The Porsche Boxster and the BMW 650 compete for the same parking spaces.
The Porsche Boxster's shorter wheelbase may produce a less-settled highway ride but a nimbler feel in daily traffic than the BMW.
Handling
With their comparable turning circles, the Boxster and the 650 quite certainly handle almost the same into and out of tight spots.
Drivetrain
The BMW 650 has a larger engine than the Porsche. Bear in mind that smaller engines typically get better gas mileage, but smaller engines can be stressed more.
Torque is the force that lets you accelerate quickly, and in this respect, the BMW is tremendously more powerful than the Porsche Boxster.
Warranty
The BMW 650 and the Porsche have the same basic after-sale protection.