You don't actually NEED the kit. You can buy individual jets at the dealer, online or from many independent bike shops. Much less money involved that way.

As for recommending something, you need to be a bit more specific with what you have done already.
Do you currently or plan to have a high flow air filter. I see that you have a wrapped header. Is it free flowing as well? This will determine where to start with the pilot jet size as well as the main jet size.

Well my opinion would be that the 155 main should be fine. If anything it may be too big. I would suggest the purchase of a 152.5 as well since the jets are only about 3 bucks each. As for the pilot? There I would go to at least a #55 minimum. That open exhaust and the high flow air filter are really leaning out the mix. I run a 55 in my setup with the stock filter and open pipe and my idle mix screw is at 2 & 1/4 turns. Most folks don't like to go much further than that out before going the next size up. So for 15 or so bucks you can have 2 of each type jet and play with the combination to hit the mark.

I've found jets at the local HD dealer for $3.

The size is stamped into the brass of the jet.  It's small but it's there.

I bought my jets from the dealer for 3 bucks each. If they are charging you 6-9 bucks each you should also ask for the Vaseline.

I was looking around for jets for a friend's S40.

The HD here told me they'd have to have a part number to look them up.  

All of the online places seem to selling them in packages of 4.  I assume they mean you have to buy 4 main jets of the same size at a time.  Looks like buying jets just got 4 times as expensive as it was a few months ago.  

So the "they only cost $3 a piece" should now be "they only cost $12, but you get 3 spares".