Actually if you do a search you will see that gains from a good DP alone will net you more gains that the software from the DP.
A good DP alone will net you more gains that the software from the DP????:word:
Way to give terrible information. Find me one dyno that shows more gains from a DP than you can get with a DP and software. Now if you consider 5hp a good gain then by all means, do a DP with no software.
To answer the OP's second question, no it wont hurt the car to run for a while till you can get the reflash, but like he said, you might get a check engine light. If the light doesnt bother you proceed about your buisness.
All this is assuming you are staying with a Stg1 flash. Go to stg 2 2and you will likely see those gains over stock.
My last dyno i put down 249HP and 305ft/lb. Im running Revo Stg2, ATP DP, EVOms Intake.