I agree with everyone that saying not to worry about GPA, PCAT. Although it's an old version, Tech's '06-'07 catalog specifically states that only the interview day activities goes towards the adcom's ranking of candidates. The individuals weights were 12.5% essay, 12.5% thinking test, 25% group, 50% interview. They've since dropped the essay, but they probably still weigh the interview the most.
Don't worry so much about GPA, PCAT. There's probably a bias towards people with high GPA, PCAT posting stats. We all got a clean slate when we received the interview invitation.