Apple claims M3 p-cores are 15% faster, and e-cores are 30% faster.
For M2, e-cores were 40% of p-cores
Base M3 Pro -> (5×1.15+6×0.4×1.3)/(6+4×0.4) is 17% faster than M2 Pro
Upgraded M2 Pro -> (6×1.15+6×0.4×1.3)/(8+4×0.4) is 4% faster than M2 Pro
Base is still decent bump. Otherwise, just jump straight to M3 Max.
Sorry, I meant to compare upgraded M3 Pro to upgraded M2 Pro.
Will edit my comment to reflect that.