opt is still f1, so you don't have to pay ss and medicare tax.

with only 14k income, I don't think you need to pay too much tax. btw, study tax board on MIT, there're plenty tips.

as to reporting tax for the year with half F1 and half H1, I still used 5k treaty deduction. no problem.

some $$$ vs status, which one is more important? focus on big issue, mm.

and last, congratuations on your job offer!