On the Meeting level, dash to the dumpsters near the start point, pick up the two car bombs, walk slowly to the sewer and enter. From here you go to another sewer exit, and the car is parked on top of the hole. The second target requires that you wait in the sewer exit behind the building near the second car, and sneak up to knock out the driver while he's taking a leak. Change into his clothes, walk slowly out to the car, place bomb, and then slowly enter the sewer (you can use the one next to the car, the guards won't notice). Run to your entrance sewer and walk away to victory.