Hey sorry for getting on this post a little late
But if the supercharger is anything like the one built for the tC please stay far away unless they deal with some serious quality issues. No offense to many of the good parts that TRD makes for other cars/trucks, the parts offered for the tC were less than durable. The tC supercharger was centrifugal, and most likely the FR-S will be too. TRD didn't have an intercooler for the supercharger and most small boost supercharger setups don't need them.
The result will probably be a centrifugal supercharger non-intercooled set to around ~5psi with about 35-40HP boost to the engine. This way they can go with a simple reflash of the ECU without upgrading injectors and maintaining minimal if any impact to MPG. The setup would probably cost around $2500-$3000 as that was how much it cost to get them installed from dealers for the tC. Really simple install actually so it shouldn't take many hours of labor.
The flaws and reason for the discontinued SC for the tC was due to a weak torque bar that connected the pulley to the compressor. It was known to actually warp and/or break off the pulley with aggressive throttle input. I.e. launching the car. Also the reflash for the SC made the tC run really lean and caused check engine problems. Worse still owners couldn't attribute problems of the SC as faults with the TRD unit and dealers didn't have to fix/pay for damages under warranty. If TRD can fix these problems (stop stealing other company's products and rebadging them and actually putting in R&D) then the SC would be a very cost effective boost for power output.