The Callaway X-16's are a pretty good set, but the R-300 shaft, being a "regular" flex, may (or may not) be beneficial for you.
My advice....for that price, I'd get 'em, because you'll lose no value in them if they aren't for you, and if they work as good or better than the Lynx you currently have, you could probably let the Lynx go for a small amount.
However....as many might advise you, if you get rid of that "first" set....chances are, down the road, you'll want to get them back.
For the money you are talking here...get the Callaways, and go from there.
You'll probably not need to upgrade again for a while, until you feel that the stiff shafts might benefit you more, and like I said....the Callaway irons will be a good value to the next person, and you won't lose much (if any) should you upgrade within a year.
Just my "newbie" advice