It that wire twisted-pair?
No, it didn't look twisted but I wasn't sure. How much more of your extension wiring is not twisted-pair?
Forgive me if I missed anything, but have you dealt with the bell wire yet?If not, and you have extensions, the rewards of isolating the bell wire in the presence of interference can be quite phenomenal...
Octal alot of us would be interested to see your results as modem stats graphs if you could get hold of an HG612 or compatible router that works with DSLstats this would be great