This may be an early question to ask, but I wonder how long people are planning on burning in the SP3K for? I’m not familiar with AK so I don’t know if they are good straight out the box or whether they need to run for a good number of hours.
I have the SP2000 and my experience is that there's really no burn-in and more of a warm-up time for the oscillators to be optimally stable (usually 30 minutes or earlier of continuous playback in my experience). Your IEMs are sensitive enough to notice it where the sound will be a bit unnerving and then after warm-up, the sound will relax and all the microdetails and dynamics will flow effortlessly