I have ecutek flash. The flash is calibrated to have near stock feel in the overall behaviour of the car. Mine was done in 2005, before ecutek "locked" their flashes from tuners. I can alter my map by using Openecu (soon!!!) as the mod list grows. New flashes can not be altered. That is, after you pay the initial fee for the license, and upgrade, you will need to pay again to get a reflash.
As far as driveability, it is excellent!!! Car feels stock, just a bit more agressive, or maybe it's just the power and time since the original flash.
I like it...
Best way to falsh for small mods depends on brand preferance. Some people like AP, others Utek. A respectale tuner in my area likes AP better for a daily driver. But small incrimental mods can be flashed for with openecu or ecuexplorer (google it). There are instructions on their sites. You will need a tactrix cable to hook up to your ecu and a new file, whereever you get it.
drive = freedom