Currently it's possible by the end of Chapter 3 to have maxed out upgrades for Thermal Series dynamos and flux cells.

However fluxducts (i.e. Pipez energy pipes) are configured only to pull FE at a rate of 1024 FE/t. A flux cell can easily be upgraded to output 8000 FE/t or more and can go as high as 24000 (I think).

Allowing endpoint upgrades for Pipez for, say, 4096, 16384 and 65536 FE/t would prevent us having to make large inefficient arrangements of cells and ducts simply to get output of more than 1024 FE/t from a single battery cell. The ducts themselves can carry any amount of power, it's just the extraction points that have been hobbled at 1024. In "vanilla Pipez" you upgrade the connections you want to extract more power with.

Ingredients could be the same tiers of Create and Thermal Series mechanisms/components as used in the rest of the modpack, i.e. copper, invar, enderium.