my 94 ls400 has a vibration during acceleration and more so when car shifts into overdrive at low speed. the large resonator that is directly behind the two manifold flanges rattles when engine is revved. to replace the resonator is ridiculous cost for a california emmisions car. can a regular muffler be used instead? or maybe just a plain pipe since there are no o2 sensors in this resonator? a local shop can fabricate just about anything and i was wondering what will work best at quieting this lexus down?