SlammedGs3

Wats up guys iam a new member sorry if i posted this in the wrong area. I have a 2001 gs300 with a set of 20" wheels and tanabe drop and kybs recently i have been hearing a really loud and annoying banging noise from underneath my centerconsole when i come to a complete stop and when i hit the gas from a dead stop. I took the car to three different shops spent about $1200 and nothing has been done I had the ball joints and control arms replaced. Noise still there and now there telling me they think its the tranny mount or driveshaft coupling ?? Please help me before i spend 10,000 trying to get something fixed!!! thanks guys