The Twin Scroll turbos are excellent. To the best of my
knowledge, there has never been a problem with the S
vehicles equipped with then. The original S models had
Superchargers, which had to rebuilt when they neared
100K. Most people steer clear of them because they are
not covered under warranty due to expiration. However,
once this is done, they run better than new because
everything is broken in. Shop for vehicles with service
records if you don't turn your own wrenches. My family
and I have rebuilt several "totaled and salvaged"
vehicles. Once you understand what's going on, they
are still laborious to maintain due to the FWD and ABS
components that become brittle and eventually fail, just
like all BMW's.
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