Can't say much about rear wheel dyno results on the GT3. I can tell you however a lot about engine testing dyno results and those weren't impressive at all. None of the tested engines had 360 HP.

Regarding the number 300: where do you have it from. From my knowledge, the new GT3 won't be limited...same as with the GT2. As long as there is demand, they'll build it.

Don't always trust what dealers tell you...some of them just want to sell their cars.