Sorry about the loss of your e53, glad to hear your parents made it out safe however. The e70 3.0 diesel may be the best option for you if you want comprable performance to your 4.4, but don't want to pay for the 4.8.

I would also really look at a used e70 still under factory warranty, but with the extended CPO warranty.

The e70:
3.0 260 HP and 225 ft-lbs of torque
3.0d 265 HP and 425 ft-lbs of torque (at 1700 RPM no less)
4.8 350 HP and 350 ft-lbs of torque

The e53:
3.0 225 HP and 214 ft-lbs torque
4.4 315 HP and 324 ft-lbs torque
4.8 355 HP and 369 ft-lbs torque