From a lad I know who works in the oil industry, I asked him about changing oil in my mainly track car:
Biggest issue with track days is viscosity due to temporary fuel dilution and temperature (due to full throttle everywhere). Oil life will be affected as oxidation doubles with every 10C. Turbo cars without adequate cooling are especially susceptible.
For something that's road with a track day once every service, I see no issue with standard drains. Something like your DC5 I would probably look at shorter mileage, but then you probably don't do enough miles to make a difference and time based requirements come it (eg 1/yr). Plus you are driving it to a from the track and this is a great way to burn off fuel in the sump. I've seen 500mile samples from a S2000 race car hitting 9% fuel dilution.
Really the best way to look at oil life is a factor of engine on time, temperature and cold starts. This is what many algorithms of 'active' longlife servicing are based on.