Am new to Subaru after Supras and Cossies hence one or two queries to see what is normal. I have a standard 01 WRX Wagon. Gearbox/clutch judders especially when cold.
Engine sounds a bit rough/misfiring on tickover

Advice would be appreciated

 

Clutches are a weak point. Often judder when cold, but that's about as bad as it gets with mine (MY00). Having said that, some people have had them replaced (under warranty) a number of times. If it's bad, get it round to a dealer and see what they say.

Can't help on the other thing, sorry.