N54 Rail pressure loose

[Slavo]

Hello

While I’m tuning with MHD my Z4 35i, I started loosing rail pressure. Before with lower boost it holds bottom value 128 Bars but now it drop to 58 Bars.
LPFP Walbro 450
HPFP OEM last changed at 30000km, now I have 80000km.
If it is failure HPFP what is my alternatives?
New OEM HPFP from BMW or exist some high quality alternative?
No DME failure codes with HPFP only misfires on valve 6.

Thanx

Slavo