H1b Transfer and Ext with I140 approved

[rupeshrajagopalan]

Hi,

I got an offer from my client to join them full time. I have I140 approved with my current employer under EB3 and my 6th yr H1B ext is around Sept 2013.

My client is going to take care of all the H1B and GC processing.

1. So is it safe to switch to my client at this stage?
   
2. How much time will it take if my client files my H1B transfer and GC process under EB2 in premium processing?
   
3. or is it safe to switch job after i get my ext in Sept 2013?
   
4. Now since i have my I140 approved from my current employer (I have the original I140 with myself) and incase i switch job and he withdraws the I140 can i still file for H1B ext with my client during sept 2013?