Toilets, Sinks, Showers, Tubs and Disposals - Replace shower stems

Good Morning.Problem: I need to replace stems in a fiberglass single piece shower surround. It seems that the original installer did not think that some day stems may have to be pulled. The diam. of the holes in the surround that the stems come out of, are just big enough for the stems, and not a socket to remove the stem. My question is what kind of a cutting tool should I use to enlarge the hole without cracking the fiberglass. I will have to cut around the stem. As always, thanks in advance

You don't need to cut anything.
You just need a set of valve sockets to find the one that fits your shower valves.
http://doityourself.com/ori/60x60/5672449.jpg
VALVE SOCKET SET
These are available at any plumbing supply or here at DIY.com for $12.99.
Turn off the water, remove the handles and then use a socket to remove the valves to replace the washer on the end of the valves and possibly the o-rings.
Check the seats in the shower body with a flashlight and your fingertip for pitting and corrosion. You may need to replace the threaded seats, also, which will require an inexpensive valve seat tool.
Good luck!
Mike

Mike, the problem is the hole is not big enough to put the socket in