@ktz392837 Agreed. Regarding G.INP, I now effectively have the same thing but it's the Broadcom proprietary equivalent called “PhyR”(Tx) or some such thing, on ADSL2. It gives increased reliability depending more or less on the type of noise distribution that you experience and then this may or may not be sacrificed, the reliability put back again, and exchanged for more speed. You can always make it less reliable, by increasing the size of constellations (ie greater bit loading / bits-per bin) or by smaller/shorter FEC overheads if you have any. It is always a trade-off. I haven't had PhyRTx long but I suspect it is one part of the reason for the huge reliability improvement, but unfortunately three other upgrades were done at the same time, so I can't tell which was responsible.
I use 3dB downstream target SNRM on ADSL2 which gives me around 15-20% more speed compared with 6dB. I can reconfigure BT remotely to change downstream target from one to the other, or even a range of higher and much more conservative options. With very good modems a 3dB target is good enough to still be reliable, not so with less good modems on an ultra long or variable line. But don't listen to me anyway, as I have zero experience of VDSL2. :-)