Hacking will not stop anything from working properly as long as you don't cheat in online games and get yourself banned, and even then it's only a simple Wi-Fi ban, they don't brick your console or anything (this isn't M$
) Since you're going the USB route, don't use cIOSCORP/DarkCORP. It's kind of like Extreme Makeover: Wii Edition, except it's completely unnecessary and doesn't give you anything useful. In fact, you really don't need to patch ANY IOS below 200 with the possible exception of your SM IOS (IOS70 for SM4.2, IOS80 for SM4.3). Anything else can be done in slots >200 (i.e. IOS236 installer rather than patching IOS36 itself).
If you get lucky and have SM 4.2, you can just use BannerBomb v2. If not, you will need one of those games, but you will only need them once. Regardless of which you do, the process is fairly straightforward. Download the HackMii Installer and copy the installer .elf file to the root of your SD card and name it boot.elf. Then, if you have a folder named private on your SD card, rename it in order to not interfere with the exploits. Next, download the files for whatever exploit you will be using and extract them to the SD card as well (BannerBomb, Indiana Pwns, Smash Stack, etc). Most of them are packaged so you can just extract to the root of the SD card, but follow the directions. Then, just follow the directions for the exploit (for BannerBomb, you start with the SD card NOT in the Wii). This usually involved navigating menus or following some in-game directions and should be pretty simple. When you're done, you can rename the private folder back (you can delete the private folder containing the exploit).
If you're on 4.2, I would suggest doing an official update AFTER installing HBC in order to get all of the latest IOSes, including IOS58, which HBC will want. Then move boot.elf from the root of your card to /apps/hackmii (you can name the folder anything as long as it's a folder inside of /apps) and re-run the installer by going into HBC and selecting it from there. If your Wii comes with 4.3 you can skip this step. The reason for this is because if you don't have IOS58 installed when you run the HackMii installer (i.e. if you were on 4.2 at the time) it will pick a different IOS to run on and then you won't get USB2.0 support in newer homebrew (IOS58 is the only official IOS with USB2.0 support). By reinstalling after the update you will fix that.