Hi, welcome to the LOC and congratulations on the IS200d purchase.
As Wendle suggests avoid the automatic car washes and do the job by hand, it will preserve the paint and you get the added satisfaction of admiring the end result performed by your own efforts.
What I tend to do with my alloys is remove them twice a year to clean the insides, wash them with the normal car wash/wax stuff when on the car then dry them off before applying some wheel seal wax.
Lexus alloys have in the past been notorious for paint peeling and corrosion but with a bit of effort this can be avoided or at least the finish maintained for longer.