(AP) — Kyle Busch had just won a NASCAR Xfinity race — his first time back on that series after being injured in a February accident — when he confidently eyed the next day's Sprint Cup event. Less than four months ago, it was fair to wonder if either of them would be a factor in stock-car racing this season, but they both came away with victories last weekend at Michigan International Speedway. More of what is the unknown is what comes from this, and that is the pep in the step of the crew members, the genuine chemistry and the feel on the shop floor. With two victories this season, Kurt Busch has little to worry about in terms of making the Chase for the Sprint Cup championship. Kurt Busch missed the first three Cup races this season because he was suspended amid allegations of domestic assault on an ex-girlfriend. Kurt Busch, now with Stewart-Haas Racing, had to use his backup car in Sunday's race after a mishap at practice two days earlier.