is this true?

 

Yes. The whole purpose of the synchros I believe is to compensate for unmatched revs when shifting gears in normal driving.

 

Not unless you're double clutching. Other wise you're just decreasing clutch wear.
3rd gear -> push in clutch -> shift to neutral -> let out clutch/ rev up engine -> push in clutch -> shift to 2nd -> let out clutch

 

Thanks