In short, there may not be a factory turbo BRZ in the offing in the short term. But there's a performance enhanced version in the works falling under the STi banner.
A prototype wearing STi badges was spotted a few weeks ago lapping Germany's Nurburgring, confirming the car's existence. The prototype featured popular performance mods such as a large rear wing, aerodynamic body kit, lowered suspension, large alloy wheels and a sports exhaust.
Whether there was a turbo under the bonnet is open to conjecture though all other STi models in the past have had forced induction. The BRZ STI will be revealed in quarter two 2013 and informed sources say it will forgo a turbocharger due to a lack of space under the hood.
Despite this, peak output should still rise from the BRZ's 150kW rating to somewhere around 165-172kW thanks to changes to the exhaust system and variable valve timing. Subaru has said in the past that there was no space for an intercooler and its required piping in the BRZ's engine bay.
However a number of engine tuning specialists have encountered no such problem when fitting a turbo to customer's BRZs or Toyota 86s. Another hurdle, likely easily overcome, is that a turbocharger would go against the purist sports car philosophy Subaru engineer's had originally envisioned for the BRZ.
Give us a break.... A supercharger is also said to have been ruled out due to a loss in the car's fuel economy, though it's more likely Subaru doesn't want the BRZ STI encroaching on the performance of its next-generation WRX. The good news is that the relatively mild mods being applied to the BRZ STI should equate to a relatively low price rise.