I feel the next challenges should be set on significantly shorter tracks. A perfect lap on the Nordschleife would take years.
Ok in case people can't be arsed doing the Nurburgring challenge. Here are a few more for varying tastes.
The challenges are all with set cars, as any open challenges ends up with everyone using the same car anyway.
For the front wheel drive crew:
1998 Honda Civic Type R
Engine: Power limit of 300HP
Drivetrain: Gearbox must remain standard, everything else free
Suspension: free
Brakes: free
Tyres: Sports Mediums
Body: Standard, no lightening or cages allowed
Track: Autumn Ring Reverse, Gran Turismo Mode, all driver aids off
For the drifters:
2005 BMW M5
Engine: Exhaust, racing chip and oil change free. The rest standard
Drivetrain: Standard
Suspension: Standard
Brakes: Standard
Tyres: Normal-Road
Body: Standard
Track: Midfield Raceway, Gran Turismo Mode, all driver aids off
For the four wheel drive junkies:
1996 Subaru Sti Version III
Engine: Free
Drivetrain: Free
Suspension: Free
Brakes: Free
Tyres: Race Mediums
Body: Free
Track: Tsukuba Raceway, Gran Turismo mode, all driver aids off
For the race car fans:
Any closed wheel car (No Formula 1 cars)
Tyres are free but everything else must be standard. No big turbo upgrades.
Track: Circuit de la Sarthe 1 (with chicanes), Gran Turismo mode, all driver aids off
Basically I have tried to keep the cars available to everyone. They should be easy enough to purchase and you won't need a massive budget bar the last one. Also a stock car, a lightly modified, an all out car and a race car. Obviously this all works on honesty, no over modifying cars. This is meant to be fun, not sheep stations. Just a virtual test of driver skill and perhaps encourage people to dig out GT4, its a great game
I will put up some benchmarks very soon.