Considering good placements and packages, which branch should I opt for: EXTC or IT in the KJ Somaiya College of Engineering?

My sister studied at KJSCE and grabbed an offer to work with TCS. So you should not concern yourself about placements because it is excellent. It's an autonomous institute, so more companies are visiting now.

If you're joining KJSCE because your goal is MBA then keep in mind that even if you amass good work experience, it matters from where you have gained that experience from. For example, having experience in the mechanical field won't get you the IT job you aspire to. So choose the branch that interests you because you'll have to spend 4 precious years in that. 

Who knows, even after 4 years of engineering with 3 years of work experience making it a total of 7 years, you might notice huge changes in your thought process. And even after its completion, when you go for placements, your field of study in UG will matter. Let’s say you are appearing for a managerial post in an IT firm, then you will definitely have a better preference if you did your UG in IT or CSE. 

It’s good to think ahead but don’t just choose a branch based on the placement.