coil pack-how hard to install?

I'm one of those people who only seems to visit this board when I need
something - sorry!

After reading a million posts here and on Miatanet, I have
self-diagnosed that my 2000 miata needs a new coil pack.

So I call the dealer, and they want $250 for the part, and he said
"about $38 in labor". Not too bad, I s'pose, but one of the many coil
pack posts led me to call Mazmart. There, I can get the part for $150,
and he said he'd ship it to me for free.

So, I doubt the dealer would install someone elses's (used?) part, so
how hard would this be for me (actually my relatively car-savvy dad)
to install? For only $38 in labor, it must not be too difficult,
right? (I've been known to be wrong about such assumptions before.)

Might I find instructions online somewhere to tackle this?

By the way, I'm 9 months out of warranty (aarrgghh), and when I told
the dealer my problem, he said that a coil pack problem is very rare
in the miata and he's betting it's the plugs. Which, as I've read from
all the posts, seems very much to NOT be the case, but I didn't feel
like arguing with him.

what a pain!

thanks so much!

jamie