Megan, its a smart thing you did about the M370 and this is what some of the ppl were asking about that. Can I ask what you've modified besides the bolt holes? Did you do a before and after tune, just to make sure its worthwhile doing this mod.
Not sure if you can add gains from first tune to second tune as there are other things involved such as temp, gear ratios
, etc etc.
I had to ask Sasha multiple times to get me dyno stuff, and he forgot to put the battery cover back in my car after the tune and which I still yet to recieve it.
You don't have too many mods and shouldn't be getting any knocking. Are you doing tune with Cobb or Uprev?
Either one, try getting a tune with APH as you should be paying only for a tune and that shouldn't take more than two hours... my two cents.