I'm going to install this + HotA + HDMod, and I was wondering if the version GoG sells is fully patched or if I have to hunt down some patch for it.

Oh, and since I'm here, might as well ask 2 things about the HD Launcher:

1- What is HD+? Should I turn it on?

2- Should I go for 32-bit True, 32-bit Strechable, 32-bit Strechable GDI, MMX...?

1. Install game
2. Install universal update
3. Install HD Mod and Superfix_Common 1.3 (it fixes some graphics)
4. Install HotA (launch it via HD mod)

HD Mod settings:
32 bit MMX stretchable pretty likely offers everything you'll need
turn HD+ ON
superfix common ON

HD+ is the bugfix part of the mod. If for some reason you want the vanilla game with all the bugs, turn it off. There's a complete changelog on the russian version of the HD Mod site, use google translate, it offers a very good translation.

Things to notice:
- HD Mod disables game intro
- If you get the CD error after starting the game, turn ON noCD/DVD option in HD mod