Guess I should put my primary focus in to perspective:
Most concerned is replacing the the frame rails. If I screw up thte project, this is where it can happen.
Second, is tying in the front of the car with the rear, as the car is a unibody and only two rinky-dink rails run from the front of the car to under the car seats.
Last is adding any additional structural support, not necessarily an entire cage, but something to provide minimal flexing to the car if/when the LS motor goes in next winter. The last step ca be accomplished next winter, as an el-cheapo KA24de from a 97 240sx will go in till then