My maxima sounds like its got a little bit of an exhaust leak. before i got it from my parents, they took it into Courtesy Nissan for an inspection, and were told that the rear exhaust manifold is cracked, but you got to drop the tranny to get to it. First, is this BS? its a vg motor with an auto tranny. 2nd, are any performance manifolds or headers availalbe, or just y pipes?