More importantly, how do you know if your car has already been flashed with a remap?
I enquired about having a remap for my used 4/4, the guy told me there was no way to tell if it had already been done. He suggested I pay for the remap, have it downloaded and if it didn't make any difference then I'd know it had been done previously! Still had to pay the full price though .
You could get a dyno test, which should give a pretty good idea.