I recently upgraded to IPD sways and all endlinks for my turbo. I also dropped in new control arm bushings 5k miles ago. CV Boots replaced at the same time.

Recently I noticed that if I pull into a parking spot fast, and later come back and pull the car into reverse at or near full lock there's a loud THUD from my front end. it comes from the driver's side (but could be both) and is so loud I don't just hear it but feel it throughout the car. It's annoying as hell.

I suspect it will occur if I stop at redlight quickly and accelerate from stop.

I suspected spring seats, but can't see how that could be at fault without it making the noise over bumps also.
Checked the transmission bushing (although a longshot) and it's fine.
Checked the upper engine mount (longshot) and is fine.

Under the car I don't see any worne pieces of metal where there could be contact.

Checked control arm to see if hitting the sway bar and it's not.

I can't imagine what it is, and before I put in new H&Rs I want to figure it out. Suggestions welcome.