The frame mod is supposed to be a winner - basically you add 50mm into the frame, in the down tube and between the downtube and swingarm pivot.
A smart man would have held onto a spare frame to make the mod easier to his own RT1 race bike project... apparently I'm not a smart man...
Both the people I spoke to who have done it, gave it the big thumbs up (Firko and a bloke at the Nats).
Nifty has been racing one to good effect as a pre-70 bike (got third in the pre-70 250s at the Nationals and was easily the best place trail bike in the class). He's not a big forum poster but hopefully he'll pip up in this thread.