I don't know if it's already been mentioned, but www.autoenginuity.com.

Has bi-directional support for most makes, however that usually has to be purchased seperately. Supports Mode 6 data, OBD readiness testing, etc... Plus, it's USB and runs on a PC so you can log data for as long as you like.

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A.S.E Tech A1,A6,A7,A8 & MVAC 609 + EPA 608

Unless stated otherwise, any question I ask is about my greymarket 1985 380SEL.