Suspension & Brakes - Hard to Describe Suspension Problem

So I'm having an issue with my car. It's a 01 WS6 6spd has only 38k miles on it. I have the SLP/Bilstein lowering spring and shock/strut combo and 18" wheels. I am getting a weird hollow banging (the "sound") when I go over bumps. The bump doesn't have to be anything major to cause the "sound" to occur. Sometimes it happens and sometimes it doesn't. It is very weird, sounds like the sway bar is loose, but I checked it and it's on there fine.

Anyone have any clue or any methods I can use to troubleshoot this. I know it's hard for anyone to definitively say what it is or isn't, but I am looking for suggestions as I am out of luck.

SFC's on chassis or exhaust banging undercarriage?

I have sub fram connectors (welded in). I've hit the exhaust with a rubber mallet to see if it was making the noise and I couldn't rule it out 100% like I said very weird sound.

Torque your lcas

Torque your lcas

lower control arms?

Check your trans mount too.

Thanks guys.

So I'm having an issue with my car. It's a 01 WS6 6spd has only 38k miles on it. I have the SLP/Bilstein lowering spring and shock/strut combo and 18" wheels. I am getting a weird hollow banging (the "sound") when I go over bumps. The bump doesn't have to be anything major to cause the "sound" to occur. Sometimes it happens and sometimes it doesn't. It is very weird, sounds like the sway bar is loose, but I checked it and it's on there fine.

Anyone have any clue or any methods I can use to troubleshoot this. I know it's hard for anyone to definitively say what it is or isn't, but I am looking for suggestions as I am out of luck.

Have you made any recent changes? Where is the sound coming from?

I bet it's the exhaust hitting the PHB brace.... :)