Opting M.Tech after B.Tech is a good choice. This increases your knowledge and experience of working with tools. Which ultimately add a positive point for your placements. You would get a good and higher post if your are a PG candidate. And you may also get an opportunity to work in foreign for the particular company. 

Hello, 

As you mentioned that you will probably do you engineering from IIT. Let me tell you that government colleges provides good placements with a handsome package.

Always remember that you have to look and shine different to get good placements  

Some of the topmost companies in which you might get placed with their package are listed below:

• TATA group - 5 to 6 LPA
• Tech mahindra - 4 to 5. 5LPA
• Siemens- 4 to 5 LPA
• Bosch- 3.5 to 5 LPA
• Larsen and turbo 4 to 6 LPA

The above mentioned companies are listed with their minimum package per annum.

I hope this would help you  For further queries write me down in the comment box  

I am also persuaing mechanical engineering. there are a lots of scopes if you can keep up a good cgpa. Tata steel, jindal all takes an iitian with high packages with almost 10 lakh. you can also go abroad and get your m,tech degree. moreover me is a very intersesting subject.