This is the first UOA I have personally submitted. It was taken on my Brother In-Laws 2017 WRX. 127,221kms on odometer 9,457km OCI. Let's see if I read this correctly please correct me if I'm wrong anywhere. The iron seems to be relatively low, being a boxer motor it is most likely wear metals from the crankshaft/thrust bearings. Aluminum is more than likely Cylinder/piston materials and the copper is going to come from the cooler on this car. Silicon would be dirt contamination, air filter was dirty and changed at this OCI. OAI says TBN is slightly low; maybe, but it's not even half the value of the starting TBN. I say it's still well within specs. I'm surprised they "estimated" the fuel dilution @ >1%. I thought this is where OAI/Polaris shines over Blackstone. This was also a point of interest for me as this engine has been known to be a fuel diluter in earlier years. He is however running a Cobb stage 1 map on the car, maybe the fuel mapping is improved there. Either way with the cST @ 11.4 it doesn't seem to me like fuel dilution is an issue. Overall, I'm pretty impressed with the results. I'm thinking increasing the OCI to 15,000kms should not be an issue with normal driving (no track use). Any input?