Performance
With that kind of horsepower, the Porsche Boxster is a legitimate speedster.
Regarding horsepower, the Porsche Boxster packs quite a punch and will knock the Cooper S down a few rungs. On the other hand, remember that high horsepower engines often command higher insurance premiums.
Handling
With their similar turning circles, the MINI Cooper S and the Boxster definitely handle about the same into and out of tight spots.
Drivetrain
The MINI's engine is tremendously smaller than the Porsche Boxster's. Note that smaller engines can be stressed more; however, smaller engines typically get better gas mileage.
Torque is the force that lets you accelerate quickly, and in this respect, the Boxster is significantly more powerful than the MINI Cooper S.
Utility
Drivers with frequent child-duty might favor the MINI Cooper S over the Porsche Boxster.
Comfort
While the front cabin in the MINI Cooper S offers a bit more head room than the Porsche Boxster, there really isn't much of a difference.
Dimensions
Your wallet will hurt more every time you fill up the Porsche Boxster than the MINI Cooper S because of its larger tank.
The MINI Cooper S fits in smaller parking spaces than the Porsche Boxster.
Cost
The destination charge is a standard charge for transporting the vehicle from its point of origin to the dealer. The MINI Cooper S is significantly cheaper to get to the dealership than the Porsche.
The Porsche Boxster is tremendously costlier than the MINI Cooper S when it comes to MSRP.
Overview
The Porsche and the MINI Cooper S have the same basic after-sale protection.