2000 Honda Accord EGR valve? Really?

Computer problem
2000 Honda Accord 4 cyl Automatic 116725 miles

had a P0304 misfire code. Had the CEL reset. Couple days later, CEL back on, another P0304 misfire fault and a P1399 pending misfire. No noticeable noises or feelings to indicate anything wrong until today when after getting off the freeway the engine felt like it was about to die (it didn't, but it felt really really close)

here's what the auto place came up with:

*the distributer cap, rotor, plug and plug wires are okay
*the ignition system components are okay (intake system has no vacuum leak)
*fuel pressure regulator not leaking
*injector functioning properly
*EGR valve actuates when power is supplied and has no restriction

they recommend replacing the valve cover gasket, EGR valve gasket and something about the intake manifold. They want to do a valve adjustment (must be done cold, they said) and inspect and clean EGR passages. For $508!

should I let them do all that? If not, what should I have them do? How can I tell them what I want them to do if I don't know anything about cars? Won't they just technotalk my face off and make me feel like they are right and I am dumb?

please help, I don't have $500 but I need to maintain my car!