There are a lot of factors here... you probably need to sit down with your partner and develop a performance specification. To say you need a SAR bird is a vague thing. It's like saying "I need a motor vehicle".
Are you working:
Offshore?
Mountains?
Hot?
Heavy?
What radius of action do you need?
Long Range?
Fuel Available?
EMS?
Who's paying for this?
What's the budget?
Who maintains it?
How you gonna stay current?
Winching?
Slinging?
Cabin space?
And those are all before my morning coffee...