Yes the clutch is totally different. I have a stock one I could take comparo pictures of if you wanted, but it's moot because they aren't interchangeable.
You aren't changing the engines power or the grip at the tires, so the stock clutch is probably fine. My car runs bigger stickier tires, will have more power, and good suspension so I went ahead and had the clamp load increased and added extra straps. Clutch choice is important, the wrong material or the wrong construction can make it suck to drive or not last long, or both. This stage one I have is good for general purpose use, but I will probably put a JBRacing/PTT ultralight setup on it at some point to save even more weight.