Attached are saome pic's
The stagea pump is 38mm dia and 90mm long (mainbody, not including the plastic plug bit)
R34 GTR pump is 55mm dia and 105mm long
As you can see there is a big size difference. I can mount the GTR pump with sock in the craddle, but no hope of fitting the lid on
Does the series 1 stagea pump just clip to the bottom of the tank with no anti starvation/swirl baffles around it?
If it does, then the series 2 lid probably is not that important.
Chook, I did see somewhere (maybe on nengun or greenline site), the Sard bumps are Bosch rebadged.
Answer to your question in regards to which flow rate, get a pump to suit your power goal. A pump that flows way too much can have a negative effect, as the excess fuel gets returned to tank and gets heated by the engine bay in the process