Two years was long enough for the current owner to apparently enjoy this ultra-rare McLaren P1 XP05 prototype. The car has, once again, surfaced for sale.

Road & Track first spotted the experimental prototype for sale again and reported it on Thursday. It's listed via British retailer Tom Hartley JNR, and hopefully, the luxury car site finds this deserving piece of machinery a home for life. Truly, it's a P1 for the McLaren collector enthusiast. We say that because this isn't a regular production P1 at all. 

2013 McLaren P1 XP05 Experimental Prototype is for sale

2013 McLaren P1 XP05 Experimental Prototype is for sale

The XP05 is one of 14 experimental prototype cars McLaren built. The British supercar firm used these cars to test various parts for the production P1 and sent them to the most extreme places on the planet for rigorous examination. Some of them went to Death Valley for heat testing, while others tested traction on Arctic lakes. This particular prototype was used for transmission and fuel injection testing.

2013 McLaren P1 XP05 Experimental Prototype is for sale

2013 McLaren P1 XP05 Experimental Prototype is for sale

Most of the prototype cars were destroyed for crash-testing purposes, but those that did make it out alive were completely stripped down and rebuilt to McLaren factory standards. While the running gear and chassis bear all the signs of a prototype tester, the bodywork and all components McLaren deemed necessary were completely rebuilt or replaced. The previous owner, when taking delivery, decided to finish the hybrid supercar in traditional McLaren Orange. The car also features numerous options from the McLaren Special Operations department, though what those are isn't shared in the listing. MSO sure knows how to make a supercar look and feel extra special.

The car also comes with its build book (with testing notes from the development process), scale model, and documented history.

Knowing its story and history, we think the car is absolutely worth its $1.67 million asking price at current exchange rates. Not to mention, the new owner will still get a 986 horsepower supercar.