I want to apply Early Action to Stanford due to the greater likelihood of acceptance, but it's too late for me to take the recommended two SAT Subject Tests before the application deadline. Should I risk applying Early Action without Subject Test scores, or should I wait and apply Regular Decision so that I have time to take two Subject Tests and submit my scores?
It depends on whether you want to further emphasize your skills in certain academic areas. For example, if many of the extracurriculars and academic achievements you had in high school revolved around Biology, then you should think about taking the Biology SAT II to provide further evidence of your passion and expertise. If you're going to take a Subject Test that you plan on submitting to Stanford, you should also be confident that your scores will be perfect or close to perfect.
If you're unsure about one or both of these factors (and would be taking the Subject Tests just to take them), then I say you should go ahead an apply Early Action without the addition of Subject Test scores. Here's a quote from the Stanford admissions website to put your mind at ease:
SAT Subject Tests are recommended but not required. Applicants who do not take SAT Subject Tests will not be at a disadvantage.