Hello Anagha Huskur  ,

BITSAT is not as tough as Advanced. But timing plays a major role in BITSAT. 

What your plan should be :

•  A good score in BITSAT is easily achievable, considering it is pretty easy. That brings me to the next point.
• Practice! Practice! Practice! Get some book with BITSAT type papers. There is one by Arihant called BITSAT which I hear is good. Do 3 papers per day. That adds up to 9 hrs of paper-solving. This is help you increase your speed and accuracy. You don't need to be super good with PCM to crack BITSAT, you just need the right approach. And solving papers will help you hone that part of your skill.
• Spend 3 hours evaluating what you did. Where you lacked, which topics are your strong points? Also see the solutions for the questions you almost got. Plan on the exam a bit. Basically, everything about paper solving.

If you can do this everyday for the next 16 days, you will get in BITS Goa/Hyd atleast. And that is very good in itself and you will achieve your aim of getting BITS Hyderabad. but moreover you dont have a mere of 16 days but you have more in your hand. So go for it. Manage your time accordingly.

Competitive exams are not a test of your knowledge. They just test how good you are in solving those type of questions. BITSAT tests you on speed and accuracy. No tricks, nothing. You might have even seen many questions before if you have done rigorous work in your high school.

Finally, some random points:

• All the people around me who performed decent enough in JEE/AIEEE, like me, my sidey, etc. took BITSAT pretty lite. Most of them were not hoping to come here. So, if you prepare for it, you are at an advantage.
• I know people who didn't clear JEE or didn't get into the the top 15,000 in Mains and still ended up with CS in Pilani. And they are pretty smart people, mind you. As I said, competitive exams just judge your approach in them. Use it! and use it well to your advantage.
• I think if I was given an option of 16 days of pain with 4 years of BITS, I would choose BITS, no doubt. So, it is actually worth it, and it's doable.

So, go on! Make your way!

Now coming to your second part:

There is nothing called ECE in BITS, instead there is E&E and E&I.

Cutoff of Electrical and Electronics Stream:

BITS Pilani : 338

BITS Goa : 308

BITS Hyderabad : 298

Cutoff of Electronics and Instrumentation Stream:

BITS Pilani : 319

BITS Goa : 289

BITS Hyderabad : 286

Hope it helps!

All the best!