MBA/PGDM

Hi,
The answer of this question is completely depends upon the following factors:
(1) Your capability and choice: If you are interested in integrated course of MBA then you may go because this integration will save your time to find college after graduation. But there is huge negative side as well. The major negativity of integrated MBA is that you will no longer be able to gain practical industry experience until you complete your MBA. Only 1-2 internships you will get. This makes negative impact during your interview because industry generally prefers the order "Graduation + Work Experience + MBA (or PG). With integration of MBA you can't show this work experience.
(2) Your college Placement. Make sure that after doing Integrated MBA your placement should be with those students who are doing their post-graduation not just with graduation because there are some institutions who gives admission for BBA-MBA but placement is along with BBA students. Based on these factors it totally depends on you that whether integrated MBA is up hand or just MBA of 2 years.
My personal opinion: You should to choose MBA of 2 years after gaining some real time company experience.

It is advisable to continue your stream of ME. As this give you in-depth knowledge of your graduation and helps you to land up in core engineering jobs. But nowadays the combination of "B.Tech + MBA" is really in great demand by companies. So it may be the wise choice if do MBA after graduation. Although there is not any specialization which is designed for 'engineers' but you may choose the stream like HR or 'Sales-Marketing'. Because in order to do MBA in finance, IB, economics you requires a great knowledge of accountancy and business mathematical economics which is not possible in engineering. So my suggestion is you may opt for HR or Sales. This field has great opportunity with attractive pay packages to deserving candidates. Provided your academia should be strong and your college do have strong global-industrial network.