90 Integra GS: Problems Galore

I just recently bought an Acura Integra with a stock honda b16a1 1.8L efi.. The odo is busted so i dont know the true mileage but i would guess somewhere in the 120xxx range.. The previous owner put an AEM short ram intake, a new cat, and resonator on it, and also advanced the timing from 16(stock) to 26. Tried to smog the vehicle, but it failed epically. took it to a mechanic who ran a compression check and valves 1 and 2 sat at 200psi, 3 sat at 184psi, and valve 4 ran at 90psi. He said the reason for this is a bad head gasket.. But from my limited understanding of cars, aren't gaskets made with metal rings to help prevent this sort of thing? The low compression would mean a bad valve right? Also, just recently (3 days prior to this post) the tensioner pulley for the a/c compressor belt came completely off, there is oil leakage.. is this due to the bolt that holds the pulley opening up the engine block? or should i inspect the oil pan for impact trauma from when the pulley shot out from under the car? Any information or suggestions would be greatly appreciated.

generally if compression is low, its rings or valves.. the best way to find a leak, is to clean like a mad man. clean it all up and then the leak will expose itself