Does engineering undergrad performance matter for masters in management admission? In Masters in Management (MSc Mgmt/MIM) admissions, how much weight is generally given by the Adcom to the applicant's undergrad performance, especially if it's an unrelated one like engineering?

Does it have any bearing if the applicant's undergrad performance is poor but his other credentials are excellent?

What kind of credentials should such an applicant aim to acquire before applying (Other than the GMAT, TOEFL, etc)?
I'll speak from my own experience.

I had only a 2.9 GPA in my major, Economics. But I had a 3.5 overall.

What may have helped me was my GMAT score (over 750). In any event, I got into several top level MBA programs, including the one of my choice.

It helps to work a year or two before applying to an MBA program. A "gap year" (or more) is probably more valuable for this degree than for other graduate degrees.