I don't mean to be rude, but I have driven older 911s with about 150, maybe 200 horsepower and can confirm that it's pretty easy to lose the rear end on one even with minimal power. also, a heavier car, maybe a holden commondore or a jaguar XJ, is fine with 300 horsepower, yes, but something like a 911 or a corvette (I've had the pleasure of driving an LS1 C5 corvette convertible, so speaking from experience here) is a bit unstable even with relatively small power like that.
now, I'm not calling you a liar, but everything I've heard about the 997/1 911 GT2 points towards an extremely unstable car.
are you sure you didn't have some kind of advanced traction control off?
are you sure it's a GT2 and not a GT3 or a turbo?
also, the GT2 in your picture clearly isn't stock, as the stock 997/1 GT2 has a divider in the sidepod, as does the stock 997/1 turbo. only the 996 GT2s and 997/2 GT2 RSs have sidepods without dividers.
300 HP isnt a lot. A regular midsized sedan can have 300 HP easily.
now I'm sorry about the double post, as I understand that's a bit of a no-no here, but what do you think a regular midsize sedan is?
a 5-series or an A6 come with a mid-level 300 BHP motor, yes, but those are premium midsize sedan. a regular midsize sedan would be a camry, an accord, a malibu, an avensis, an insignia or a passat. all of those cars have, at best, a V6 that puts out about 200 horsepower, and at the base model, an 125-or-so horsepower I4.
edit: thanks to whomever combined my posts!