Found
this tool, and it is extremely handy. Shows you what parts you are missing, if you're missing any villages, everything.
I know I said I wouldn't do the challenges, but I found some easy tricks that make them a lot easier:
For Air challenges, don't get in the plane provided. Instead, call the black market dealer, and get a
Rowlinson K22.
It's fast enough to get to each checkpoint quickly, and nimble enough to make the toughest turns. When fully upgraded it becomes fast enough to complete a 3-star difficulty race with over 1min30 left on the clock.
For Ground challenges, get a bike. It's more useful on roads because it can swerve through traffic easier than a car (not as wide).
The bike I prefer is the
Makoto MS 260X, available at the black market. When upgraded, it can run fast enough to get to each checkpoint quicker than 10 seconds, and if you turn or brake, it doesn't slide out like the
Cougar. It doesn't go up steep hills that easily though, and large bumps in the road, or going completely off road will almost certainly knock you off. Another option is the
Hamaya Y250S. Only found in traffic, it's not too fast, yet still speedy, and it's completely stable, but still nimble.
For Sea challenges, get a
MTA Powerrun 77.
Again, available at the black market. It has a slow start speed, but an insanely high top speed. Only downside is that it's not that sturdy, despite the turret when completely upgraded, and doing a jump across land can easily flip your boat. Start the race before you order it, though, as you usually get one anyway.
For Basejump challenges, good fucking luck. Use your hook as efficiently as possible, and hope that your chute doesn't fuck up your orientation.