There's no way to update the Model X for LIDAR. It's structurally incapable of supporting any of the existing LIDAR systems in production or currently in development. The same could arguably be said for the Model S, due to the front monopane windshield.

Even if these vehicles could be modified to support LIDAR systems, the modifications alone would likely cost upwards of $10,000 per vehicle, not including the cost of the LIDAR system (currently $20,000 for cheapest system offering 360 coverage). Those costs would bankrupt Tesla.

At some point, Musk needs to learn to keep his mouth shut. A sales person making these types of claims can be disregarded on the grounds that a sales person may not have the authority to bind the company. But if the CEO says the same things, customers who purchase cars based on the CEO's representations can definitely sue the company for failure to deliver promised goods.

Then all Musk needs to do is not allow Tesla to "come to find" out that LIDAR is necessary before the technology has advanced to such a degree that they can retrofit the Model X and to do so when the cost has come down sufficiently to afford it.

Which is what he's currently doing. When they do finally admit that LIDAR is necessary, Elon will play the "no body could have foreseen this situation and we were operating under the best knowledge at the time" card.

He's bullshit all the way down.