CPS issue...maybe

[Sean Coriaty]

Obtained my second 200q20v avant last month; 207k miles, paid 4k. Pearl on
black sport, nice shape cosmetically.
Screaming clutch TO bearing held up during the 1k mile drive to NH from MI.
Week or two after short commuting, seemed to be running rich (20 MPG,
occasional fuel smell).
Changed oil, hit the highway, WOT from the toll booth then sudden loss of
power.
Kept running under very low power for several seconds. Tried giving it more
gas with little effect; noticed boost readout was erratic- eg, 1.6 then 0.4then
1.7 then 0.2 all within a second or two. Pulled over, it stalled. Would turn
over but no start. Popped hood, noticed exhaust manifold was glowing red
hot...in daylight.
Been suspecting turbo was burning oil, since I'd notice oil smoke coming
from that side of hood after WOT runs and it was making a max of 1.6 bar
boost and turbine louder than last 200q20v.
No Audi specialists within reasonable tow range, so it went to the stealer
(I know, I know)
Stealer said they "pulled tons of codes", then said they spent 2 hours
trying to diagnose no-start but couldn't.
Administered mild verbal abuse to tech rep.
Next day, they claimed the crankshaft position sensor isn't putting out a
signal and asked me to authorize $500 to replace it.
Asked them if they're SURE the CPS is responsible for no-start condition;
they said yes. Have my doubts, but time will tell...
CPS due to be installed tomorrow.
If CPS is truly bad, would it have resulted in the red-hot exhaust manifold?
Wondering if anyone has any input.
Sean
1991 200tq20v Avant 209k