The difference in the Exam portion is that CWE does not have to take the practical portion, But the major differnce is with CWE one must be a certified welder and demostrate documented training hours/ with CWI only -all that is needed is 5 years min, in related work and pass 3 portion of test.
no disrespect intended 803056 the test score difference would apply for CWI verus CAWI. All this information can be found at the certification section of the AWS home page.