V8 TDI lowering

Hello, everybody.
I've been looking for springs/ suspension for my V8 TDI for quite some time. except K.A.W. 60/30, KW thread variant 1 and a H&R coilover suspension I found nothing. I want to drive the original 20" 9 spokes, so don't be so deep. -30 mm would already be enough, the original sports suspension springs cost already around 700€. Does anyone have experience or advice? The problem is that the 3.3 TDI has a VA load of 1340 KG.

Mfg Florian