A quick tip about the 145s: They are much easier to use, so you might want to buy the uni with 145s installed, then switch later when you want a smoother, faster ride. That's just a suggested option though - you'll still be able to ride around starting with shorter cranks, and you should be happy either way.
Also, welcome to the forums and I hope you find the investment worthwhile%2Pr
Those bolts are what hold ISIS cranks onto the unicycle. They'll come with the unicycle, so you don't need to buy them. To remove one, you'll need an 8mm allen key, which is usually built into most crank pullers.
I'm pretty sure the one I used is here
It has served me well, and removes both cotterless and ISIS cranks. It's also a lot less expensive than what you'll find on unicycle.com (abbreviated UDC on the forums%2Pr
In reply to my post you mentioned getting the 145's as a second set of cranks and that I would need a puller.
Do you have a link to the right puller? I haven't had a uni in 20 + years and have no idea which puller does what, and also on unicycle.com I see Isis bolts http://www.unicycle.com/isis-bolts.html, do I need those too?