Ahh c'mon no difference with the blue spring
In that case I think I was already there with stock everything (except an ASP o-ring TPC, non ported.) Prior to my running out of paint I was at 600 on the stab and around 270-280, tpc 2 turns in. Only ran about 10 balls through it at that setting before I ran out of measurable paint.
Regarding efficiency I guess it depends on ones definition. Right now like I'm sure most or all non regulated Phantoms I get decent shot count if one is ok with a decreasing FPS on each shot. I'm not, I'd much rather have 25 shots north of 270 than 40 ranging from 280 to 220 from a 12ie, the latter being some peoples definition of an efficient Phantom.