i have a 2008 bmw 2.5 3.0 auto cab how much can i chip it too? please

For starters, which is it, a 2.5 or 3.0 e92? Also, you have two things going against you, the drop top and the slushbox. This is not the best ride to mod. If you did a cold air intake, and exhaust with the ECU remapping, you might see an additional 40-50 w.h.p.

In 2008 we no longer used the 2.5 engine they were all 3L. So do you have a turbo engine or a non turbo engine. If turbo then you have some options to make really good power from a tune. If you have the non turbo N52 engine then that engine has already been tuned to it's max output thats why a lot of tuners don't even mess with remapping its DME. You would be better off with a good cold air intake and a free flow exhaust.

Double check the production date on the inside of the driver's door.