And it will also consume the competion with balls of fire from it's eyes and bolts of thunder from it's arse...
Look man, I may believe it will have an available Turbo motor as an option, but I don't think it'll be all that. I don't believe road and track (they said the Scion line was going to pick up the Celica) Celica is a youth-oriented car, the kind of power you are describing would be more akin to an older MR-2 or Supra. I could see a Supra/Celica, like back in the day; A Supra powerplant in a celica chassis, but that seems a bit much these days. The "Hybrid" supra you speak of is actually a Lexus model entering production next year, it features a V6 gasoline engine and a Hybrid Synergy motor assist system (like the one on the prius) that makes the Engine/drivetrain perform more like it has a V8 engine under the Hood
, while still retaining the fuel economy of a small v6 engine. It is not a Supra (They wouldn't make the supra a hybrid, it's a prestige car!)
I doubt the celica will see an engine larger than 2.0 liters, Turbo may be an option on higher trim levels, and HP output will most likely be competitive with other makes out there (around 160 HP for base model- about 220 HP or so for higher trim levels).
250+ HP cars are in a different class than the celica (you're now competing with the likes of the 350Z, RX-8, and WRX STi, which is a job for the supra or possibly the MR-2S, not the lowly celica) If the Celica has a HP option that puts it in that range, then the price will be out of the range of the average consumer. Yes, maybe they'll make a GT4 again, but it definitely will be more expensive than other celica models by a significant margin. And considering the GT4 didn't do that well the last time they brought it to the US market, I doubt they will try it again.