I think once the installed base of Model S is of sufficient size then Tesla will begin to "mine" that installed base with various offerings.... such as performance add ons of various kinds (both software and hardware). Volvo did this with my XC60, offering a new chip for the ECM that provided 25 more HP for about $1,500 bucks.
As a first step in that direction, the LUDICRIS upgrade for current P85D owners was announced. For $5K + Labor Tesla will upgrade your contactors and fuse giving your battery pack 1500 AMP output for 2.8 second 0-60 times. There is not much detail on this particular program yet. No labor costs are defined and it is still unclear if the battery pack itself will be upgraded from 85 kWh to 90 kWh. More details will flush out over the coming weeks. BTW, the parts to do the upgrade are NOT at the SC's yet nor have any of the front line techs been trained on the upgrade from what I have been told. That will happen soon.