My car was mapped by Mark Shead who has a pretty good reputation for getting the mapping right, we have agreed to do some more cold start mapping to try and solve the issue.
The fuel tank is small, yes. It is a road car but only designed to take around 30 litres and this includes the swirl pot as it is a fun car. the Tank was made out of ally and is sited right in the middle of the car for weight distribution and safety within the cage. It is not a race car, it will be used on Track, the strip but mainly the road.
The pump does indeed prime as you say. The engine, as far as we know is 100% standard 200 block and makes 469 bhp using the Borg Warner twin scroll. No lary cams or compression tweaks....we will know more when Mark rebuilds as a proper 500+ spec.