I agree with Indymac: The F22C engine usually doesn't burn oil, however if it's aggressively driven, he may be losing a lot of oil through the PCV valve. Switching oils on this engine has worked for some S2000 owners, so it's worth a try. Otherwise, the OP may want to consider Krank Vents (note: this suggestion is specific to the S2000 engine).
I've seen numerous UOAs on this engine, and I can't recall ever seeing one using Mobil 1 that didn't shear a fair amount.