I am having a hard time finding an STi. Just curious to know if this financing special will get extended.

In the past, once Subaru has introduced special financing or cash back on a model, it stays around or increases throughout the course of that MY, and then the next model starts without any incentives. They haven't offered anything on the STi in the past though, so I suppose it might change.

If you tell them that it was an incentive for you to buy the Sti, the WILL extend it.