I have a very very gentle tap/rattle at about 1800 rpm, been told it could be the big end bearings?

my Impreza ownership days may be short lived!

 

Could be the Big Ends? Who told you that?

Could be the exhaust

Could be the Tappets

Could be the manifold

Could be the radio

Could be the gearbox

In other words, it could be anything ........ talk is cheap - get it checked out as you are doing - but, stop worrying!

 

Been told its Piston slap, as only happens when cold and goes away after 10 minutes of driving - so not as bad a first though!