Well after enough research and trying to get rid of the annoying P0420 code, found a company who makes a affordable rear o2 simulators with heater.
I'm in the testing phase right now.
The company in their email said they full money back guarantee this to work with Subaru. $40 for this or about the same for a replacement rear o2 sensor I said, why not!

Will be updating with pictures but it's pretty darn simple install.

Link to seller and simulator