Utility
The Lexus IS 350C will most definitely prove friendlier than the Porsche Boxster for those of you with frequent child-cargo.
Performance
With that kind of horsepower, both the Porsche and the IS 350C are genuine speedsters.
Dimensions
The IS 350C is tremendously heavier than the Boxster.
The Porsche's tank is roughly the same size as the Lexus's, though the Lexus's is a bit larger.
The Porsche Boxster and the Lexus IS 350C compete for the same parking spaces.
The Porsche's shorter wheelbase will give a sprier feel in daily traffic. On the flip side, the Lexus IS 350C 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. It costs about the same to get the Lexus IS 350C to the dealership as the Porsche Boxster.
The Lexus IS 350C is substantially less pricey than the Porsche Boxster as far as MSRP.
Handling
With its tighter turning circle, the IS 350C is quite certainly sprier than the Boxster, something to consider if you do a lot of city driving; however, bear in mind that a vehicle with a tight turning circle may feel a bit twitchy on the highway.
Drivetrain
The Lexus IS 350C has a more massive engine than the Boxster. Remember that smaller engines typically get better gas mileage, but a smaller engine usually has to work a little harder.
The IS 350C packs quite a wallop compared to the Porsche with respect to torque, which is the force that lets you accelerate quickly.
The Boxster could learn a lesson or two from the IS 350C when it comes to torque.
Comfort
While the front cabin in the Porsche Boxster offers a bit more head room than the Lexus IS 350C, there honestly isn't much of a difference.
Warranty
The Lexus IS 350C and the Porsche Boxster have the same basic warranty.