so i use premium gas in my car 90 octane but with each full tank i add a bottle of STP fuel additive octane booster. the past few weeks i have noticed a squeeking coming from the engine around the turbo/power steering area. im pretty sure its the turbo. its a squealing noise that only happens after i warm up my car from a cold start. while its warming it doesnt do it, but when i start driving it will do it for about 10-15 minutes max then it fades away and wont do it again till i repeat the proccess from cold start. i really dont think the STP additive has anything to do with it, but i would like to know what others think about this situation? im going to make an appointment with subaru and take it in cause if it is the turbo its covered under warranty. any kind of help or input will be appreciated. thanks. and if i get a chance i will try and record a video of it while its making the sound but its hard to do that cuase im driving the car.