Just had chance to look back at this thread. I've now done the Alpina flash for DDE6 variants plenty of times. The Alpina has uprated hardware over the 320d and yet the alpina dde6 flash gives the car greater performance over the stock bmw flash.
So would the above not be similar for a 318d -> 320d dde7??? Obviously without the hardware mods you wouldn't get the full effect. But as with the Alpina upgrade you night get something...