You'll need several things:
An up to date copy of Saints Row IV
I got mine from Steam: Saints Row 3 & 4 and all of the DLC available. Can't beat the deal, don't bother pirating it because this game is super fun.
https://ninite.com/notepadplusplus/
Auto installer for the amazing Notepad++ (recommended)
https://www.saintsrowmods.com/forum/...l-cheats.3212/
Additional cheats mod for Saints Row 4
Adds several cheats and allows you to use them without impacting your game stats (recommended)
https://www.saintsrowmods.com/forum/...s-row-iv.4651/
Sandbox++ for Saints Row IV
Next you can download the modified LUA file I attached and overwrite the original from Sandbox++.
E + [
Reads out variable levels, shows you your current height, height multiplier, and grow level.
E + ]
Grow, 5 levels with differing sizes and text (enable No HUD in Sandbox++ or the additional cheats mod to hide the text and readouts) and on finish starts over while increasing the growth!
I felt the original 25 set stepped height levels was not very fun for the process fans among us, but the way this is coded anyone can tweak the values to suit their tastes (slower growth, faster growth, starting large and shrinking) and feel free to edit my dialogue.