I have had my 02sti in at the dealers to have a look at a very light knocking noise when the engine is cold, this only appears when ambient is below 16deg and below 2000rpm ish. I changed the oil to a 15-40 which made it a lot better. Anyway the dealer has said he thinks it may be marginal piston slap but could not 100% confirm due to a high ambient. I have been reading on here that a cam belt tensioner can give the same noise to piston slap. I have also read that piston slap should not be a problem on phase 2 engines. Can anyone recccomend someone in the brighton area to get a second opinion?