Modeling a collision process in detail could take a team and a few years, but we can look at the overall energy. Two stars with the mass of the Sun each, colliding head-on at 10% the speed of light, have a total kinetic energy of 1.8*10^45 J. That's about a factor 10 above a type Ia supernova. That's more than fusing all hydrogen and helium to heavier elements could release - we can expect some weird fusion processes to happen but they won't change the released energy by more than a factor 2. It will look like a very bright supernova in some way. Life on nearby stars would have a bad time, but planets would keep orbiting their stars without any large-scale changes. For planets orbiting one of the two colliding stars the outcome could depend on where in the orbit they are - "behind" or "ahead" of the collision.