Forza Horizon 4 is turning into Trackmania tomorrow, with the arrival of a free Horizon Super7 mode. The mode basically works like this: the Super7 event is comprised of seven user-created stunt-oriented courses, all chosen at random, and all skippable if they prove too hard (or low effort). You can also browse user-created courses, so assuming there's community uptake, you shouldn't be lacking new gauntlets to overcome.
But it's the creation aspect that sounds really fun. According to IGN, who had advance hands-on with the update, the Blueprint Builder lets you create courses anywhere on the FH4 map, which seems to include the Lego and Fortune Island regions. Once you've set the track, you'll be able to spice it up with ramps and other stuff. The video above gives you a good idea of what to expect, it's basically Trackmania with a dash of GTA Online's Cunning Stunts.
Otherwise the creation tools are reminiscent of those found in Forza Horizon 3: you can set the challenge type, the time of day, the weather conditions, and what kind of music the challenge will default to.
Honestly, I think any racing game is markedly improved by the inclusion of ridiculous, unrealistic stunts, so I'll be reinstalling Forza Horizon 4 ahead of the December 8 (December 9 in Australia) roll out of Series7. This new update comes a year after the last major Forza Horizon 4 addition, which was a vehicular battle royale mode.