Hard to comment on this question as it's really not clear what you are asking...
Are you asking what happens when you update the scoring data? <- Nothing really but that depends on what campaigns you have that are triggered by scoring changes.
Do scoring updates pass to SFDC? <- Any fields mapped between Marketo and SFDC will be updated (assuming your scoring is mapped so no action needed)
Are you trying to understand what impacts to lead volume making these changes will result in? <- You can do some forecasting on how your volumes will change but that is dependent on your MQL threshold.
Are you asking for other best practices when it comes to changing scoring?
Can you elaborate on your question further?
Just want to make sure I cover all my bases and think through everything. Good suggestion about re-forecasting. Not sure how that fell off my list.
There are several threads on updating Lead Scoring and then doing a Score Re-set on the existing data.
Will check out the other discussions. Thanks