This is EXACTLY what I'm wondering too. Here's my synsopsis: you as the customer will not be able to go 200 if you bought the 19" wheels. For the foreseeable future.. The original wheels are likely embedded in the VIN. Think about it this way: A customer could totally lie and say that that they have the proper tires, when they haven't. WAYYYY to much liability. So the 19" cars are likely hard limited to their 163 mph. Tesla will possibly allow people to call in or send proof or something that way it can be unlocked. I mean, this could be serious. If a tire blows up at 180+ mph, or even 163 mph, you are pretty much dead.