Agusta 119 Koala is definetely a single engine helicopter. The 109 series are twins...

Having flown the odd few SAR Cabs, if you can go for one with a fully articulated head. The semi-ridgid ones I have flown have all been worse in the hover and don't ride the bumps as well.

Bigger is good as they can take more pounding and shrug it off better than the little toy ones(412 etc).