Should my mechanic be able to do the plugs wires and coil or should I use a Mazda dealer? It's probably a dumb question especially considering so many of you do your own work. What type of work would be better suited to have a dealer do?

 

It's a 2/10 in difficulty. If you can hold a screwdriver, follow instructions and place 4 things in the correct order, you can do it. Trust your mechanic to meet those criteria?

Leave any kind of problem diagnosis to the dealer or a rotary specialist. Some dealers don't know what they're doing, but at least Mazda has a book they can follow.

 

Any mechanic should be able to do it. I do it myself.

 

Have you ever replaced a smoke detector battery?

It's about that difficult only there's no danger of falling off a ladder and breaking your neck.

IIRC, you'll need a phillips screwdriver, socket wrench, 10 mm socket, and a YouTube video.
It gets easier if you also have a 12 mm socket so you can remove the strut tower bar (4 nuts and then that thing isn't in the way).

 

^Yep, you really just need to take the intake accordion tube and airbox off to get to the coils.

But I'd replace the spark plugs with the coils. Spark plugs are a bit more involved since you need a way to jack the car up.