New Ford Mustang traction issue?

I recently purchased a 2015 Ford Mustang Ecoboost and have noticed ever since i purchased it (2 months ago) that the rear tires don't have that well of traction while turning. It has Hankook Ventus S1 Noble2 and the tread wear on it is minimal since its a new car. Even when I make a turn(going 15-20 mph, low rpm), it will feel like the whole back of my car slides/drifts into alignment with the car. Almost feels as if the road is slightly wet, even on a sunny day with dry streets. Today it rained and when i was driving I had to be even more cautious. I was driving down a straight shot with no cars around me and wanted to see how well my tires grip in the rain, so i accelerated to 3500/4000 rpm and my back tires started to spin out and the back of the car started shifting hard to the right with each press of the gas. Very scary and felt like there was no tread at all, but the tires are new. I've bought new tires for my old VW(less powerful engine) and it never did that even when I floored it on a wet road, so I know it can't be the horsepower causing it. What can be the issue? Is this common with new tires or can they be defective? The tires look amazing and are very wide and look like they d grip well, but they don't… Any help or advice would be appreciated, thank you!

Added (1). On dry roads, I can floor it without this happening. Its not something that necessarily makes the car dangerous or scary to drive in normal conditions. I still LOVE driving it, just scared one day the rear might whip too much into a curb or another car.It only happens when making turns and driving on wet roads.

If the tires are fine, the "issue" is that this car might be bit too much for you. Performance cars like the Mustang are designed to burn some rubber when you hit the gas, that's part of what makes them fun. It's a bit strange that the Ecoboost turbo engine has enough power to loose traction in the low RPM, but I suppose it's possible.

Double check that the traction control is on. It's likely a button somewhere near the dash or center console. If it's on, you'll just have to practice and be careful.

Check your tire pressures at the rear. Higher pressures make the tire more responsive to bumps which make the car feel sharper. This however also means that there's less tire deformation which decreases grip.
lower tire pressures will not feel quite as sharp but they will provide a bit better grip as the tires can properly deform over the surface of the road.

if your tire pressures are too high at the rear you may find that you'll have decreased rear end grip.
add in that the ecoboost develops most of its torque very low down in the RPM range and this can become quite a problem especially in turns.

another possible reason is that your aliignment may be out of whack and you could have less than optimal tire contact with the road.

i know it may not show but take a good look at the rear tires and their wear. Look for uneven wear patterns. Do the sidewalls show more wear than the center? What about the one sidewall more than the other? These could hint at possible alignment issues.