If it has good compression its not a valve problem, because that would cause low compression.

I would start with the plug wires. Some people have had issues with them in the past. This shop sounds less than steller, so I'm not sure I'd trust the diagnosis of the wires. Wires are pretty cheap and easy to do. I haven't heard as many issues with the coil packs.

That being said, if you want I have an extra OEM ignition coil from when I put a new engine in my car after the previous owner snapped the timing belt and grenaded the engine. I would sell it dirt cheap cause I don't need it.