Just to clarify to every new reader of this forum what I mean exactly by the significantly different Inter-17 versions I'll present three comparisons here. All European boats measured by the independent Texel handicap organisation.

EU Inter 17 (1999-2003): mainsail 13.68 sq. mtr. by 8.15 mtr luff + 15 sq. mtr spi
EU Inter 17XL (2004): mainsail 15.25 sq. mtr by 8.05 mtr luff + 17 sq. mtr spi
Inter 17R (2004-2007): mainsail 16.44 sq. mtr. by 8.53 mtr luff + 19 sq. mtr spi

EU F17 (2007- ...): not measured yet

Basically the total upwind sail area grew by 20% and the spinnaker area by 27%, the mast grew taller as well, by 0,55 mtr (almost 2 feet).

Wouter