I cheated and bought one of those one piece spec c manifolds
Yesterday I made a little in-tank anti fuel surge device whcih cost me nothing to make. Petrol weight is 1Litre = 0.711kg so for example if you were running the tank with only 20 Litres in it you are saving around 28.5kg in a wrx with a 60L tank which is very significant!
Here it is
I then added a few holes but only on the right hand side because wrx's suffer from fuel surge on long high G right hand turns. What happens is when you make a right hand turn all the fuel goes flying across the fuel tank to the left hand side and if the corner is long enough there won't be enough fuel at the pickup to power out of the corner. This starts happening on certain corners in my car at half a tank of fuel. So by having no holes on the left hand side of the anti surge tank the fuel can not escape in a right hand turn.
Right hand side
Left hand side
The fuel pump assembly also has a little pump that bring fuel back over from the left hand side and drops it above the pickup sock. I have extended this so it drops the fuel into my anti surge tank
You can see I have a cable tie wrapped around the fuel pump to hold everything in place when I slide it back into the cars fuel tank
I was able to test it on some long right hand corners near my house and it worked a treat, no sign of fuel surge with bugger all petrol in the tank!
This is where my fuel was at during testing this afternoon.