I found out the answer to my turbo question....
Taken from:
Here
Precautions for turning off a turbo engine (7M-GTE engine).
After high-speed or extended driving etc., requiring a heavy engine load, the engine shoul dbe allowed to idle as shown in the chart, before turning it off.
Driving condition and required idling time.
Normal city driving.
Idling time -- Not necessary
High-speed driving.
About 80 km/h (50 mph)
Idling time -- About 20 seconds
About 100 km/h (63 mph)
Idling time -- About 1 minute
Above 100 km/h (63 mph)
Idling time -- About 2 minutes
Steep mountain slopesdriving.
Idling time -- About 2 minutes
NOTICE:
Never turn the engine off immediately afer a heavy load. This may cause severe engine damage.