I did all my cutting with an electric angle grinder with "zip disks". I used an air die grinder/dremel with a buffer attachment to buff tight spots.
Use what you are comfortable with. Angle grinders are great because you can buff, grind, and cut with them. They are less maneuverable than a die grinder with a smaller cutting wheel, but with a steady hand you can make some nice cuts. Also, if you use zip disks you can save worn down disks to use for tight cuts later.
Just to stress safety for the DIY people, angle grinders spin
extremely fast, up to or more than 10,000 rpm. I just heard through a safety flash at work about a fella having a zip disk blow apart on him and tear open his throat. The guy died. There have been instances where zip disks have blown apart and embedded in face shields. I also know an old fellow who accidentally put his angle grinder down on a rag, and broke two fingers when it wrapped up around his hand.
You also have to use a properly rated disk for your angle grinder. Some disks may not be designed to spin as fast as your grinder can spin them.
I would highly suggest for your safety, that aside from hearing protection, gloves and a dust mask, you wear safety glasses AND a face shield. At least use a face shield.
Another thing that is not talked about alot is getting in the habit of knowing where the shrapnel will fly if a disk shatters. Always keep your vital areas out of this zone if you can. i.e. don't work the disk in line with your body, work it off to the side. Imagine the disk spinning and where the pieces will fly. Zip disks are also very thin and easy to snap. Don't work them in a manner that puts stress on them, don't lever them, they are for cutting straight lines only.
I just don't want to think that in trying to share my little project here, some damn fool will go and injure himself because I didn't indicate that there are dangers present that need to be managed. -So be careful.