So, Today I'm going to tell you guys how to Unlock every Kart Part, Alternate Title Screens, and Golden Mario.
Regular Kart Parts
First off is The Standard Kart Parts.
Basically to get the Regular Kart Parts you just have to Collect Coins, A Kart part is randomly unlocked every 30 coins. Once you reach 450 coins this changes to every 50, and once you reach 1500 coins this changes to every 100. In total Unlocking every Standard Part Requires a total of 3100 Coins.
There are many Ways to Collect coins, Game Explain has two Methods that can get you coins Quickly Via Battle mode, There is another way that uses two controllers, and turning on Smart-Steering and Auto-Acceleration on Moomoo Meadows or on Mute City.
note that you can only get 10 coins every Race/Battle
But now, for the Golden Character/Kart Parts
Gold Mario + Alternate Title Screens
To Unlock Gold Mario you must Get First Place in every Single Cup in 200cc.
To do this I Recommend using a Light Character and a Kart with a ton of Acceleration and Handling, Turning on Smart-Steering can be a Gamble, on one hand it Allows you to stay on the Track, but on the other it Prevents you from taking shortcuts and getting Purple Mini-Turbos from Drifting.
Gameplay wise, Gold Mario is an Alternate Skin of Metal Mario, and Plays Identically to Metal Mario and Pink gold Peach.
Unlocking Gold Mario also Unlocks the Alternate title Screens.
Golden Kart
To Unlock the Golden Kart You must get at least a 1 Star Rank on every Cup in Mirror Mode.
Not as bad as The Previous one, Its actually Easier, its pretty Much the same as doing a 150cc Grand Prix but the Tracks are Mirrored Left-to-Right, Just dont get confused on the Tracks and use what you would normally use for 150cc, and then You should Easily get the Gold kart in no time at all.
Golden Tires
To Unlock the Golden tires you must Beat the 150cc Time Attack Staff Ghosts on every Track.
These are Basically a 1v1 Race with only 3 Mushrooms as your only Items, the Staff Ghosts always follow the same path every single time. Its Trial and Error at most. Figure out their Paths and Know how to use every Shortcut in every Track, If you can do that you can Easily get the Golden Tires.
Golden Glider
Finally there is the Golden Glider, which Simply Requires 5000 Coins(10000 Coins in the Wii-U version).
This is Easily the Most Time Consuming one to unlock. The Same Tactics for getting Coins for the Standard Parts can be done for the Golden Glider too.
Gameplay Wise ALL of the Golden Parts Play Identically the the Standard Kart, Tires, and Glider.
And that is about it, all of the Unlockables in the Deluxe Version of Mario Kart 8
All of the Images were taken from the Mario Wiki: https://www.mariowiki.com/Mario_Kart_8_Deluxe