I have two suggestions:
A way to see your splits at checkpoints
Sloped turns or a way to build off-grid
Adding Even More:
Boost Pads, Super Boost Pads, Mega Boost Pads, Ultra Boost Pads, Random Booster, Reactor Boost Up, Super Reactor Boost Up, Mega Reactor Boost Up, Ultra Reactor Boost Up, Reactor Boost Down, Super Reactor Boost Down, Mega Reactor Boost Down, Ultra Reactor Boost Down, Extra Long Slope Up, Extra Extra Long Slope Down, Extra Long Smooth Turn, Extra Extra Long Smooth Turn, Coin and Diamond Producer, Switch and Buttons, Road with Pillar at Top, Effects, Alphanumeric Signs, Sign with Text, Sign With Images, Checkpoint Rings, Finish Rings, Split Curves, Pillar with one by one side branch, Magnetic Wheels, Vertical track bottom round, middle and top round outer corner, Vertical Rotating 45°, Loops and Twists in Roller Coaster, and Lap Counter