Electrification has arrived in the world of supercars, and the newest entrant is McLaren’s plug-in powerhouse, the Artura Spider. But this drop-top has more to offer than a little fresh air, with more power, better braking and better handling, all designed to help take the fight to the Ferrari 296 GTB. So, is this $500,000 convertible the pick of the plug-in supercars?