go big or don't bother.
all kidding aside, you will see some guys running dynojet's stage 1 or stage 7, or morley's muscle kit. i followed the veterans' advice, which is to not even bother with the stage 1. as an "all around" jet kit, go with morley's muscle kit. you'll only have fun with the stage 7 if you have many 1/4-mile stretches of backroads. know what i mean? don't get me wrong, the stage 7 is LOTS of fun, but you'll have more opportunities of fun with the morley muscle kit. of course, exercising all of your ponies all of the time isn't necessary. i don't have a morley kit, but i do have a Stage 7 augmented with velocity stacks that behaves similar to the muscle kit.
if i had to choose between the S1 and the S7, for me, I would use the same arguments I made when I decided to go with a full-up exhaust upgrade over slip-ons. If I was going to spend so much money on slip-ons, I might as well save and go for full-ups. So if I was going to spend so much money on a jet kit, I might as well save up and go for it with the S7. Both decisions to wait and save for the full experience have not disappointed me. For S1 you're talking about $130-150 for the needles and jets and get to keep your K&N filter. For the S7 you're talking about $350-400 for the jets, needles, springs, puke can, PCV hose, and the 4 individual pod filters that are sold separately.
http://www.dynojet.com/jetkits/motorcycle/yamaha.aspx#1200 http://store.knfilters.com/search/product.aspx?Prod=RU-2989
if i had to choose between the S7 and MM kits, hands down, i would choose the MM kit for my daily driver. for the price, it's a no-brainer. An MM kit will cost you $325-$375 for everything that the S7 offers plus a Muscled airbox.
http://www.morleysmuscle.com/muscle-bikes/vmax/jet-kits/jet-kits
my sincerest of advice: although I personally haven't been on a S1 setup, I truly believe that if you go with S1 you will be wanting to go with S7 or MM within a few months. for me, if I were drinking Dom P?rignon and never had Piper Heidsieck, I'll bet that the guy drinking the Piper would absolutely want a pull from my bottle of Dom.
i didn't know the first thing about carburetor jetting until only a few months ago and was able to re-jet with the help of the forum members. this forum, if you haven't figured out yet, will be the biggest asset you can ever have.