You'll notice a difference (an improvement at that!
) with doing just the sway bar! 
hyea:
Will it be enough?! Hard to say, that depends on a whole lot of things that are largely dependant upon you: how hard or gentle or aggressive or smooth you ride; to some extent where you ride ie how tight/fast/slow/cambered your roads are; your 'feelings' about how well it works; and maybe even how much your pillion rides '
with' you & the Spyder or how much they resist/react to the forces upon them during turning.... and probably a bunch more things besides that we have little knowledge about specifically &/or little ability to determine how much difference they'll make to the overall result! :dontknow: But certainly, swapping/upgrading the sway bar alone will reduce the rolling somewhat plus it'll share the load more across both front shocks & potentially avoid or at least reduce the bottoming out, and so upgrading it
WILL make a difference! :clap: And if, after ryding with the new sway bar installed, you decide that the difference it's made is not enough for you/your needs & wants, then you can move on to addressing the shocks &/or springs..... it could be that the shocks are fine, only your springs are too light for you & your pillion, your ryding style, & the conditions you ride in! :lecturef_smilie:
You
could try doing the shocks/springs first, but from what you've already told us, I'd think your biggest improvement will be gained by upgrading the 'widely recognised as not quite up to the task for many' sway bar first. Upgrading the shocks & springs will very likely make a similarly noticeable improvement to your ride, but they'd do it by firming up the entire front end feel without significantly improving the rolling/reaction to cornering relationship between each side, so your ride may become firmer in a way you/your pillion doesn't like &/or still leave you with much the same worries about the rolling & cornering..... it's generally harder to resolve body rolling & cornering issues by changing shocks & springs alone without adversely effecting anything else in the way of ride & handling than it is with upgrading the sway bar....
So it all comes back to being your choice - do the easier, cheaper, & simpler first option by upgrading the sway bar & end links, which also happens to be the option that's probably the most likely to solve your stated concerns, & then
maybe consider doing the shocks/springs later if necessary; or do the more expensive & harder (? for most ? ) to do option first, spend more money, maybe make the ride less enjoyable, and still possibly (probably??) find you
STILL NEED to do the sway bar to make the difference/improvement that you're chasing!! :shocked:
Good Luck! :thumbup: