Have you had your cylinder heads shaved for more horse power?

If so, please answer the following:
Which motor do you have (including displacement)?
How much was shaved off?
What was your compression before and after shaving?
What octane fuel is required now?
What are your general thoughts about the modification?

BTW: I am having mine modified. I have a 1999 V200TLRX which is a 3.1 liter.

THANKS!