I am flying to India (indore) through Mumbai.

My BA flight lands 9:00 AM and I have about 3 hours to go through immigration, customs and shuttle transfer to domestic terminal for Jet Airways.

Are 3 hours enough ?
Do i check in my luggage for domestic jet flight before or after i board the transfer shuttle - i.e. at international terminal or domestic terminal ?
Are there are any fast lines at immigration/ customs for business class ?

thanks,