mailing means it would take more time to reach the IRS, if you're due a refund, it will take longer to get but it would not change the amount. if you owe, late payment penalties and interest are increasing every day.so efile may be best.
the kicker, I'm not including any TT fees that may need to be paid. if due a refund and its sufficient it could be paid out of it. on the other hand if you owe, you'll have to pay by some other means..
