I have a fair number of clutch improvements on my bike.
The wet slug kit engages the clutch quicker and harder so it doesn't slip as much when your going slow.
It also increases the bite of the clutch in case you really wanted to add significant power to the bike, or haul really heavy loads.
It takes a little more time to add them clutch wise as you have to go a little deeper into the tear down, and the wet clutch has a left handed threaded nut on some models and air seems to be suggested.
A performance sheave is something else to look into if you don't mind spending a few extra bucks.
You can shim the stock sheave, and that will help with takeoff, or compensate for bigger tires.
The secondary spring determines the rpm that the motor will achieve before the bike starts going faster, and should be picked based on what kind of riding you do. Mud would be different than trails and roads.
Dr. OD pulley weights can help make up for the increased takeoff gearing from shims and sheaves by giving you back your top speed, but the weight picked effects when things happen, and tire size should be considered when picking them.
I didn't want to have to do things more than once so I called James at JBS Performance, told him what I wanted to do with the bike and he gave me a recipe of goodies that worked in harmony the first time. Wasn't just a 3 dollar shim, but you do get what you pay for.