Grand Prix implies fast action (movement of camera work, not the cars). And that, in turn, requires high bitrate to avoid block artifacts.
Option A:
If you want to break it up across a pair of 1-hour DVDs, that would work well.
Use XP mode.
Option B:
However, if you do not want to break up the content across spanning discs, then go for the 352x576 with the highest available bitrate. FR170 is always safely in the 352x576 + good bitrate range, and that runs just shy of 3 hours.
Use FR170 mode.
And if you're interested....
Technical Notes:
The switchover from 720x576 to 352x576 varies slightly from model to model. On my NTSC JVC DR-M100 recorder, that happens at either FR160 or FR165. I forget exactly -- really need to make myself a note card.
If you want to spend some time testing the exact perfect settings, record a quick segment at everything from FR150 to FR170 on a DVD-RW. Finalize, then put in the computer, and use Gspot to see what's what.
You NEVER want to use 720x576 beyond 2 hours (120 minutes, FR120, SP mode), and even 2 hours is pushing what's acceptable. Remember that most pre-HD broadcasts, as well as most consumer recording formats (like VHS) were closer to 352x576 (or 352x480 for NTSC) than they were to the Full D1 specs. Related topic:
Is SP MODE the Best DVD Recorder Mode? (NO!)
Hope that answers you.
The best?
