Was on a 2003 55cm x 270cm around 85-90litre Sonic today, and compared to the 2011,90 litre version, i think board design has improved heaps.
The front strap of the old sonic,the wall of the board has little contour,was coming out of strap all the time.
Main difference between the two boards was in bottom end. Wider in the tail and mid area the newer sonic powers up way easier,making it much faster in lighter conditions and better upwind too.
Noticed smaller diffence in big gusts,but newer sonic was still faster.