Out of all Fiat Chrysler brands, Chrysler has held a fairly low profile over the last few years, especially since the 300 SRT left the US market back in 2015. However, spy shots indicate that FCA may be considering another SRT 300. The test mule in question seems to be utilizing 315 mm tires and four-piston Brembo calipers which would indicate significant performance improvements over the current 300-horsepower, 3.6-liter Pentastar V6 found in the 300S.
Although the Chrysler 300 utilizes a majority of its parts and full chassis from the Dodge Charger, FCA has not blessed it with the 6.4-liter V8 or 6.2-liter supercharged V8 found in the Scat Pack and Hellcat. SRT 300s are still on sale in other markets outside of the United States, so it's possible this prototype might be more along the lines of a Hellcat variation. If a Hellcat Chrysler 300 were to go into production, it would likely be the first time the supercharged 6.2-liter V8 would make it to Australia as they do not have any Hellcats at this time.
The mule's body does not appear to be modified but if FCA were to drop in a Hellcat engine, we could expect the associated performance specifications to go along with it. The Drive will be sure to keep you up to date on any further developments.