IMO, anyone should think long and hard about running a drag suspension on the street. Worst setup I've ever tried.
Pretty much ruins everything about driving the car.
My work van handled better.
This also begs the question: What is the end goal of this street car?
Is it popping the wheels off the ground from a stoplight? (not hatin', I've always wanted to do this)
or
Is it launching fast out of the hole?
I'm suggesting that if the weight that you [don't] save by keeping the OEM k-member is properly transferred, that this may be a benefit for higher torque or lower geared cars. At any rate, taking that weight off of the nose as torque output increases will provide diminishing returns.
I would probably spend that money on the ass end of that thing even it's to invest in a better set of tires (or more of them since what you (OP) want will wear fast).