Hi all, looking for a bit of advice please, im getting smoke out of my exhausts on my s3 8v 310ps facelift on start up looks blue ish so assuming its oil. Only happens when its been left overnight but occasionally will do it an hour or so after being sat. Sometimes quite bad. Sometimes a quick puff. Doesnt smoke any other time. Car is a 66 plate on 27k miles. Mods are res delete, revo intake and valves programmed to stay open all the time. Any help or advice would be great thanks. Been advised it maybe valve stem seals, if so is that a big job? And rough cost please? Video link below. Thanks