[trrk]

Hi,

> now as i understand this service at 20k threshold is a major one [as told by
> the service manager], and he suggests engine oil flushing; engine part
> lubrication and a couple of other fancy things.

Engine flushing is definitely not needed at this stage.

If you have an owner's manual, just check what all should be done at this particular service and do just that as far as your servicing is concerned.

Your sluggishness and falling off the RPM should be solved by cleaning the throttle body.

The screeching is most likely the belt. The loose belt also may be a factor in the tighter power steering if the heaviness has increased recently.