I have a 2006 Forester with a popping noise when I hit a bump in the road. At 221,000 miles I knew it needed ball joints and I figured the strut/towers were the cause of the noise. So I had my mechanic install coilover/struts, ball joints and outer tie rod ends. He said it also needed a front drivers side axle and hub bearing and anti sway stabilizers. All this work was completed and I took it to a reputable alignment shop where it had new camber bolts installed and an alignment done. I have driven it about another 2,000 miles and with over $2200 invested it still makes the popping noise, both mechanics have looked it over and can't figure it out. One of them has suggested it is probably a rubber bushing but does not know for sure. Any suggestions?