are the sti pistons like the standard type regards having to put them to certain sides.

i know about the piston A & piston B, but what about them being two left, & two right.

 

any one know

 

Should be a dot on the Crown (Arrow on some Non Subaru Pistons) which faces to the Front of the engine when you install them.
All the Impreza pistons have an off-set Gudgeon pin to reduce Piston Slap,hence the dot.
If your not sure,push the Gudgeon pin halfway in and measure out towards the skirt - you should see approx. 1 to 2 mm difference side to side.
When looking from the Front of the engine :
No.1+3 Pistons have the off-set Downwards.
No.2+4 Pistons have the off-set Upwards.