Oooh... that's certainly the right symptom to be looking for.
Can you tell if you're getting more or less errors? With G.INP active, you'd be looking at the FEC rate and the retransmission-transmitted counter.
Knowing the distance and attenuation can help too. However, I know very little about the Drayteks. I'm not sure which of the two attenuation figures we should use as the Downstream attenuation. If it is the 26dB value, then that's a good speed. If it is the 18dB, then it is merely decent.
G997 is a strange one?
Power Mngt Mode: DSL_G997_PMS_L0
Line State: SHOWTIME
G.997 is all about the mechanisms for network management of a DSL physical link - which is the mechanism by which the link behaviour can be altered (such as setting the line profiel by DLM) or be manipulated (eg, by forcing a diagnostic mode).
PMS is likely to be a "power management state"; L0 likely means full showtime, with everything transmitting.