On the Customize area, you have a lot of option you can take in order to shine on our tiers, you can select your Clubs, Ball, Trail and Hole Effects.
From those options, only your Clubs have stats who can better help you during a match. You can also upgrade them when you have the required number of cards.
For all items, you have three types: Standard, Premium and VIP.
On the top of your Customize page, you can check what Club you have selected for each one of the tiers, remember that a Club from Pine Forest cannot be played on the Rocky Mountain or even the Snowy Valley. So if you have a max out Club from one tier it will only be available at that same tier.
On the Balls tab, you can select from all of the other customize items you have on your bag and also take a look at some of the amazing items you can get from Chests.