Like the wind is made easy if you have about 600k to spare. Purchase the Corvette ZR1 (C6) '09 from the dealership for 184,800 credits. Then put the race modificationsnon for around 385,000 credits, I believe. I can't remember the exact price. The buy all the remaining upgrades for it, including chassis reinforcement and soft racing tires. Now for the tuning:
For Daytona:
Aerodynamics: 35F/53R
Transmission: 261 Top Speed
Initial Torque: 10
Acceleration Sensitivity: 20
Braking Sensitivity: 10
Right Height: 5F/5R
Spring Rate: 16.6F/14.4R
Dampers(Extension): 9F/7R
Dampers(Compression): 9F/7R
Anti-Roll Bars: 3F/5R
Camber Angle(-): 2.0F/1.5R
Toe Angle: 0.0F/-0.30R
Brake Balance: 5F/7R
For this track, using this set-up, you should be able to easily win if you cut across the grass where possible.
As for the Indiana Speed Way, I don't remember what I did tuning wise, so just look that up and it will be somewhere on the Internet.
I hope I was able to help somebody!