I have narrowed my E39 M5 purchase decision to two cars. One had the VANOS rebuilt, (with warranty till 2018 or 34,000 more miles), and has what Iuld deem lackluster off the line performance. The other you can hear the VANOS tick indicating a rebuild is in order but it's performance is that of what one would expect. What I am wondering is it possible for the VANOS unit to "stick" open in a position so that the cams remain in the "advanced or retarded" mode facilitating "hotter" performance? (For lack of better verbiage I used words we used when we'd advance or retard timing by turning the distributer). Any input is appreciated.