You might as well upgrade the standard shock, and then get a better spring, tailored to your weight. Just getting the XX shock will do little, but it might be a small step up from the standard VFR shock.
The CBR1100XX is no better than the VFR800. Nothing to be had there!
I'm talking from merely a higher rated spring than the VFR point of view. Not everyone has nearly $400 to throw at the suspension, and you can pick up a XX shock for less than $50.
If you HAD to go cheap on the quick, it is a viable option for people over 200 lbs.
The 929 is a much better option. Has external reservoir, fully adjustable, same srping rate as the VFR too. You throw a spring on one of those for $80-$100 and you might have $20-$30 in the spring.