However I'll try Freetz on 06.03, will check it out.

06.03 is also shafted.  Dropped back to 05.22 working fine, sync is better.

define shafted?

I have found 05.22 has the better VDSL firmware implementation for my line.  I have tried 05.51, 06.01, .03 they ALL have lower sync than 05.22 for me.

yep, pretty typical, even more so on shorter lines.

i wouldnt be surprised if the security issue is only in the 6.0 firmware too.. (regardless, myfritz wasnt added until 5.51)

think the next move for me to make, would be to build up a freetz 5.22 firmware.