Talking of SAR helos in Army, SAR role itself is divided into 2 categories ==> SAR and CSAR
SAR is for peacetime activity, like rescue people stranded in flood, over a mountain etc, while abandon a ship in sea. Bigger helos fit for SAR role so as to carry more people in one trip. same role may also be performed by smaller helos but then they may pick only 2-3 people in one trip.
CSAR=> its role is to pick downed pilots from hostile area, thus they have to be small, agile, fast so that they ingress quickly, settle themselves among trees and descend down so that not visible over the horizon, pick 1-2 pilotsand quickly egress.
I think every helo comes with an option for winch which may be fixed when req and removed when not required. PAF is using Allouette III helos for CSAR role. Army is using Bell 412 and MI-17. Alouette III Lama helos are also used to pick stranded mountaineers in Northern areas. Few years back, a Lama helo rescued a foreign lone mountaineer from Nanga Parbat. Both the pilots were given the highest award for herioc rescue work by that country's president. (sorry forgetting the name of country).