Tesla delivered 21,577 units in the first half 2015. Tesla sees third-quarter production and deliveries of about 12,000 vehicles including a few Model X SUVs. If Tesla Q4 delivers 12000 Model Ses, that leaves 4443 Model Xes to be delivered Q4. In CC and in shareholder letter Musk spoke about problems with Model X manufacturing and also said, that those problems could interfere with Model S manufacturing; "Correct. I mean, we do think that it's going to be quite a challenging production ramp on the X, and if we are faced with a choice of deliver great – we only want to deliver great cars, so we don't want to drive to a number that's greater than our ability to deliver high quality vehicles, so – and the nature of the production ramp which is basically an exponential ramp that then becomes an S-curve, is basically for every week longer that it takes us to climb up that exponential is about an 800 vehicle reduction of the X" ----- But we actually have now produced several Model Xs off the Tesla production line, but this is a complex machine with several thousand unique components. So there are still a lot of low volume parts for suppliers on the Model X. And – but with each week, we keep building more and more Xs off the line with greater and greater part maturity. And then (17:18), we expect to do our first delivery of production of Model Xs at the end of next month. ------ Well, I think there's – some things are definitely a lot more challenging than others. And the Model X is I think a particularly challenging car to build. Maybe the hardest car to build in the world. I'm not sure what would be harder. ------ I don't want to sort of name specific suppliers, but our biggest challenges are with the second row seat, which is, it's an amazing seat, like a sculptural work of art, but a very tricky thing to get right. The falcon-wing door actually seems to probably not be a critical path item. There are some interior components, interior trim that are possibly on a critical path. But it's always hard to say exactly what lies in a critical path because it tends – these things tend to play schedule leapfrog and it's kind of a set of constraints that one day is this constraint, then the next day it's another constraint. The pace of progress is really dependent on which supplier is the slowest and least lucky. So, if a supplier has unexpected challenges which can range from force majeure to simply having to redo a design because the initial design was wrong. But when you have a complex product like the Model S with thousands of – that's dependent on thousands of suppliers, you can say that the pace of progress is determined by the thousand least lucky and slowest. But if we knew in advance which one of those would be, we would take action. So the – yeah, it's -" In shareholder letter they wrote; "We are now targeting deliveries of between 50,000 and 55,000 Model S and Model X cars in 2015. While our equipment installation and final testing of Model X is going well, there are many dependencies that could influence our Q4 production and deliveries. We are still testing the ability of many suppliers to deliver high quality production parts in quantities sufficient to meet our planned production ramp. Since production ramps rapidly late in Q4, a one-week push out of this ramp due to an issue at even a single supplier could reduce Model X production by approximately 800 units for the quarter. Furthermore, since Model S and Model X are produced on the same general assembly line, Model X production challenges could slow Model S production. Simply put, in a choice between a great product or hitting quarterly numbers, we will take the former. To build longterm value" Based on all that I think it is quite possible, that Tesla can't meet guidance's lower limit of 50k cars.