DIS-2 will not work unless you buy 2 of them. The DIS=4 is what you want assuming a stock wasted spark system. You also need two msd tach adapters and aftermarket coils since the insulation on the stock coils is not enough to prevent arcing to ground, which requires a set of plug wires to be made(it's easy to modify a set of NGK wires and install the GM terminal ends). Crane does not support a 2-step. A two step alone will not hurt the turbo. It's running the 2-step as an anti-lag type setup that will kill the turbo since you retard the timing to the point where the cylinder is firing while the exhaust valves are open.