Hey mate, I have upgraded the pump in my attesa and I was having problems with surging around corners under half tank, originally I was told by the mechanic that installed it I would need a surge tank to fix the problem. But after taking it to a different mechanic I was told differently. The 2nd mechanic took a look at it and found it to be a problem with the sock fitted to the pump being the wrong design of sock to fit this type of fuel tank. The sock was one with a right angle so when installed in the tank the sock was sticking up and around corners it would get air into it, the solution to this is to change the sock to a 45degree angled sock and position it so it faced down into the tank.
This fixed my problem and now I can run the car with no surging even after the low fuel warning light is on, where before I had to take corners slow under a half tank.