512MB NVIDIA 8600 / 512MB ATI 3870 (Modern integrated graphics like Intel Iris Xe will run this easily).
However, I can offer a of GTA IV: Complete Edition and its official updates, which you can use as a reference or basis for your own writing: gtaiv complete edition build 14009960 repack new
A: For pure stability? Yes. The Steam version forces the Rockstar Launcher, which can corrupt save files. This repack is a standalone, offline-first experience. 512MB NVIDIA 8600 / 512MB ATI 3870 (Modern