2002 Subaru Legacy L Thumping during acceleration

I have a 2002 Subaru Legacy L with a 2.5 L 165 HP Horizontal 4 engine and 119,000 miles on it. Its an awd sedan, and I haven't had issues up until this point. I let a friend drive it, and somehow she managed to go up a five foot embankment, over some tree stumps and hit a few trees. Got the car out and had it towed to a shop, they looked at it, and I have replaced two wheels, an inner and outer tie rod, a lower control arm, a sway bar linkage, and two ball joints. It drove fine until the day after the shop on my ride home from work. Whenever I hit the gas, there is a very loud thumping sound coming from what sounds and feels like under the center console. I took it back to the shop, let them drive it, they felt the thumping and put it up on a lift and said they couldn't see anything wrong. But I know something is wrong, I just don't know what to do, or what it could possibly be. Its only during acceleration, usually starting around 15-20mph and stopping around 60-65mph. Any ideas?