Hello,

Acoording to me I will go for IITM mechanical because :-

1) B.tech degree is better than a dual degree because if you are capable enough to do a B.tech from IIT you can try for a MS from abroad rather than doing a M.tech from IIT.

2) Even though there is very little difference between Madras and Kgp in terms of academic exposure and opportunities, still IITM should be preferred since Chennai is a metropolitan city whereas Kgp is a bit remote with not good connectivity.

However mechanical and electronics are two different branch, so according to your interest in these two streams you should choose your future field.

Hope this information helps.

Good luck!