That in-tank pump looks really good, especially as it is spring loaded.
With respect to the araldite on the fitting, I guess it's only there as a secondary sealant, I assume there's a brass nut on the inside which will be giving most of the seal. Did you consider PTFE tape ?
I like the tank extension, I guess that will act as a swirl pot, you'd need some serious g-forces to empty that !
I love it when people quote things as "good for xxxbhp" like it's some sort of technical measurement... Pumps are usually quoted in litres per hour at a given pressure. You should be able to find the flow rate of the injectors, times by 8 to find the absolute maximum flow requirement (injectors rarely run full open), see if the pump matches, pretty straight forward really.
Any pics of the megasquirt ?