My picks for SAR are a lance of Ferrets or, if I can get them, Rippers - simple, cheap, and capable of doing the job without tying up my heavy transports scooping up MechWarriors instead of moving infantry or supplies. They're also capable of doing several other jobs. Kestrels rate around the same and have a medevac variant you may want to look at. A Sprint can't deal with opponents, even to the extent of a Ripper firing on a few guys with rifles to run them off, meaning that unless you're the Forestry Service, you probably want something else. If you're talking about hostile penetration against more than a few guys with rifles, quit messing around with single-unit solutions and bring some attack choppers in to clear the area. If you need more infantry, attach a Karnov or a standard Kestrel to move some infantry in.
That last part is why the Word and ComStar have the best CSAR options. Pintos can go in, run some tanks off, and then actually grab the pilots.