Never really thought about it till asleepatthewheel said 'current "resident" stig', but they probably change who plays the stig each season to keep us guessing.
I havent paid enough attention to driving styles of the stig to know if it looks different at any time but it would make sense to do that.
Having said that im still fairly confident that the stig that talks is damon hill, they even had him on the show once
