I recently purchased a 07 Grand Prix GXP, V8 5.3. When I go to pass or speed up the rear end wants to bog down and kind of fish tail.
My question is how to prevent this or what to do/use to beef up rear end?

Are you sure this isn't a case of weight transfer and torque steer?

Is this rear wheel drive?

Mike it is FWD.....

I found this, at:

The Quickest Cars of 2007: $25,000 to $30,000 - Car Comparison - Feature Article - Page 0


With a stated purpose of creating a "car to run with BMWs," engineers had to seek solutions outside the norm. The most impressive and efficacious of these was the fitment of 255mm-wide, sticky Bridgestone tires in front to compliment narrower, 225mm-wide tires at the rear in order to combat endemic torque steer and understeer. It works, and even a little bit of oversteer can be coaxed from the car. Other tweaks include forged aluminum wheels, Bilstein monotube front struts, a larger rear anti-roll bar, and a 0.4-inch reduction in static ride height, which, in addition to lowering the center of gravity, increases the effective spring rate.

That what someone else suggested. Is there a way to strengthen the rear so it don't bog so much? Using heaver springs, ect.?

I think you answered your own question.