Best Integrated school (IIT Training+CBSE+Residential)

there is nothing called best. it depends more on the student than the coaching centre these days. with the cbse marks equally important, the integrated iit coaching is taking a back seat with many. yet there are few integrated schools..

MVM leads, with chennai public school and velammal in the list.
Aditya vidyashram in pondicherry has iit integrated i think.
narayana tech schools are another famous.

kota has lost its sheen with the new system of advanced and mains.

P.S. I had met a few kids who came back to muscat in the first few months because they could not hold to the pressure. you can always look at the dasa scheme for nri.