If I use the Spark Broadband tool, it says that VDSL might be possible for my address. I rang Spark to see if it was possible, but they came back with an email stating: "To receive a reliable VDSL service, line noise is required to be 15 dB or less. Your line noise is at 14.3 - 15.2 dB, unfortunately this means that the VDSL service wouldn't work on your line."

If I look at my current modem stats I see:

Upstream Downstream Current Rate (Kbps) 1092 10588
Max Rate (Kbps) 1157 10520
SNR Margin (dB) 6 11.8
Line Attenuation (dB) 13 27.1
Errors (Pkts) 0 0

Shouldn't that suffice? Also my house is about 45 meters from the connection point at the road. The cable running to the house would have been put in the ground in the early 90's. If I replace that cable with CAT6, am I likely to make much improvement? I only have one master connection in the house, coming straight from the road...