forget about s2 and s3, not even offered for the vmax. here are the installation instructions for the s1 and s7:
View attachment 4116.pdf,
View attachment 4716.pdf
just looking at the parts list that come with the kits you can see that on top of what you've mentioned, going to s7 requires, bigger MFJs and possibly PAJs, different fuel needles (the s7's are more aggressive, i.e., more tapered), air correctors, crankcase return (breather assembly), optional vboost eliminators (ie, manifolds. some guys do, some guys don't), optional slide hole widening (some guys do, some guys don't), optional velocity stacks (some guys do, some guys don't), and last but not least,
a full-up exhaust upgrade (otherwise the s7 is useless). the s1 doesn't need a more flowy exhaust, so i'm betting that you still have the stock exhaust, if not then possibly slip-ons. dynojet says you can use slipons with the s7, but the guys here will scoff at the remark, rhetorically asking dj, "who are you kidding?"
if you are thinking of s7, consider morely muscle kit instead. it has a better mid range which promises more street fun, whereas the s7 has a better top range, which promises more dragstrip fun that can only be had with 10 seconds of WOT
Regards from my Taptalking Hercules Android