We bought a 2015 Subaru Forester to replace our 2002 Honda CRV. The new CRV’s do not have as much linear room in them for the harp, but the new Foresters do. The rear seats fold down flat, which makes loading the pedal harp a breeze. Of course, my pedal harp is an 85 GP, about 70 inches tall, so it is not as large as a full-size concert grand. I believe yours is a L&H 15, so I think it would fit well in the Forester. Be sure to take the transport cover of the harp with you when you shop for a new car, to make sure the harp will fit without having to lug the actual heavy harp around!
Gas mileage in the Forester has been averaging about 35 miles to the gallon, so we are very pleased with it!