Turning is alll about weight transfer. Remove the front preload spacers and install preload spacers in the rear. The tires play a factor as well, Tall sidewall tires tend to fold over under hard turning.
Are you running a good quality 5 cell hump pack? If you are using AA batteries for the reciever that will kill the servos torque. Do not adjust the servo saver past the HPI manual settings. It will cause the servo to fail.
The XL comes with a 120oz steering servo, it does a good job when everything is set right.
Toe out increases steering response, toe in decreases it. Adjust the front steering tie rods until the wheels are "toad" (lol) out just a tick. This will make the truck respond to steering input much faster.