im on the lookout for a decat downpipe, how cant i tell what size pipe my 95 impreza has. ive seen a downpipe for sale but its 3", how can i check its the right size ie 2.5 or 3"?

dave

 

may sound stupid but carnt you just measure it

 

the downpipe might be 3" to 2.5" flange to bolt onto oe exhaust if you have the oe cat in place then you need a downpipe that has the 2.5" flange.Both previous classics ive owned had a H&S 3" openneck decat with 2.5 flange
Ask the seller what size is it at centre pipe.If its 3" all the way then you would need a 3" exhaust also.