Just to add a tip on maxing out your manual stat.Go to the Factory entrance at the Slums and you will see a hammer icon for building your own ramp/etc. One of the walls in this park already has a half pipe section in it for doing jumps. Just add another half pipe section on the other side of the park using the build tool.
So when you do a jump, land with the
for an invert, the press
then
for a manual, balance it until you get to the other half pipe, jump with
and then repeat.
Its a bit tedious but it has to be the quickest and easiest way to max out the 140,000 feet stat as you dont have to reload manual challenges after you fail them and the jumps will automatically keep you moving in the correct direction.
I went from 98,000 feet to 120,000 feet in no time doing this. Just another 20,000 to trick out!