Well of course we are only looking at this from the side. This could be a test mule. However there seems to be more defined pieces than what you would typically find on a test mule. For example why would there be what appears to be a defined 3 part front grill? Why would Toyota go to the extreme on a test mule to have a scalloped door extending into both front and rear fenders. While this type of scalloping is something to be found on a mid-engined design it is clear that Subaru and Toyota are incorporating design cues from a few different cars(this has already been brought up on the new 2022 BRZ). The only thing that seems a little unusual to me are the front and side sill extensions. Typically that would be found on an ST version of the BRZ or perhaps a possibly hotted up TRD version of the 86. Otherwise the scalloped doors, the 3 part front grill, the different headlamps, the slightly raised section of hood in the center as well as the slightly different designed quarter window would indicate a logical type of design difference to indicate an 86. A mule would not have all these defined design cues. The original mule that came out a month or so before the BRZ reveal, I think, reflects "both" cars. What we are seeing here would look to me like a final design for the 86.