If your bus can get through emmisions inspections (which I understand you have regularly in USA) without the EGR, then ditch it. If you need to have it in place, you need to make it work again. It's as simple as that.

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If you have a 5 cylinder, you don't need a stereo.

1999 Audi A6 quattro
1990 Volkswagen Golf CL Syncro
1987 Audi Coupe quattro