it's even more competitive than EE, bascially, the department cuts off the applicants with lower than 3.3 CGPA directly, to guarantee the acceptance, 3.5 CGPA is required, but this is for Mech undergraduate students. I doubt you have to take more courses(other than 45 credits required in M.Eng (mech)). So you'd better go to student affair office to get this right.