In part 4, they fit a 180 section rear tyre which "transforms" the handling. The new SV uses a 5 inch rim which means the standard 160 section tyre doesn't fit that well.
https://www.youtube.com/watch?v=hcYyJVASJVA
In part 5 (not yet posted) the bike will have a new exhaust, power commander and quick shifter and will be back on the dyno.