Whats wrong with your current carb? I seldom run into a OEM carb that needs a "kit" the parts don't wear out once since I started wrenching on cycles and ATV's back in 1970 I found a bad needle in a jap carb, the rubber tip was damaged, their is one part in the FL250 carb that wears out your talking a FL350.
I would not buy anything from that idiot first of all all he is going to do is drop ship you a carb he does not stock parts he really is not a business like you might think he is a guy selling stuff on a website in his basement he has no store front, don't be FOOLED by his crafty wording on his website that creates illusions that are just not true like the strong use of the word "we" means him and his wife.
If you have to have a new carb I would call SUDCO
http://www.sudco.com/Carburetor01.htmlOR
http://www.carbparts.com deal with them.
I would only use a Kehin on my ATV's unless they came with a Mukni from the factory the Kehin carb you can still use the cable choke, with a Mikuni carb your going to need a "kit" at a extra cost to adapt your choke to their carb.
Again whats wrong with your current carb that has you shopping for a new one?
BTW posting links to LIEwires site is forbidden on this site that loser wore out his welcome here and with this group years ago You will notice I added the URL you used to this sites word sensor list so using the tinyurl think no longer works, yeah I am a prick and its payback for all his past scams like buying up the domain pilot- odyssey.com so ALL links to that now defunked site would take you to his lame ass site, yeah he is still riding everybody else coat tails because he is a dirt bag loser with no thoughts of his own

haha FUK you Steve! yeah we will never forget all your lies and dirty bullshit of the past !