I'm pretty sure we're just exiting the tail end of the 'too early' stage as far as aftermarket parts go. I haven't gotten any confirmation on my hypothesis, but I imagine that the market for parts is going to increase if Toyota takes the iA under its production wing. Being so, I think there'd be a harder push from TRD to start making parts, and competition would soon follow.
Speaking of parts, whatever happened to the RS*R springs / coils? Did they just drop the ball?