Assuming you can figure out how to securely mount the paddle shifters, the wiring shouldn't be too terrible. It is highly likely that the + - positions on the sport Auto correspond to two switches which are active closed. So all you would have to do is wire the paddle active closed in parallel with them. However, you would still need to use the regular shifter for P,N, or R. And it would likely not be a good thing if the paddle shifter + was active while the floor shifter - was, or vice versa. That could happen with the parallel setup if any one of the 4 switches ever stuck closed.
