M157 tune questsions,spark,cam timing

Hey all just a stab in the dark here have a customer with a 14 CLS63 amg 5.5 the m157 and would like to see what I could do for a tune on it. Ive been tuning coyote mustangs for about a year and a half so this is all new to me. I see a few suggestions for the m156 for timing and spark but im curious a good starting point if there are any do's and don'ts on these cars. I have the stock tune file to post if anytone needs it to look at it or make suggestions. The car is all stock and will be doing a 4 hour road race in a week and a half through florida and he wanted to see if I could tune it prior. thank you all