Change Jobs after 6-year H1 extension and I40 approved

[llonandes]

I have been reading the posts here about what's been on my mind but I'm still hoping to have answers/comments on my question too.

I'm considering changing employers now; after my 6th year of H1B extension and I40 being approved (H1B up to 2014). My priority date is May 2007 under EB3 category (which seems a long way from being current) so I'm wondering -

1. What impact would changing my employer have, considering my new employer successfully does my H1B Transfer before I quit my existing employer?

2. Would there be any risks if my new employer would re-file my case as EB2 instead of EB3? Is that even ethical with a Bachelors Degree and over 10 years of industry experience?

3. Could I possibly use my 2007 priority date if the existing employer would cancel the I40 case?

Would appreciate an experienced and an unbiased response. Thanks for hearing me out!