Firewall replacement

[Rob]

I need to replace this panel:
http://www.cip1.ca/PhotoGallery.asp?...113-813-111-BH

I'm trying to figure out what is needed, anybody ever done this ?

I'm still in the planning stages as I will need to modify the motor setup to make sure it doesn't interfere with the firewall.

Can this be done with the body on the car or will I need to get it off.
Can I remove the original body panel (well, what's left of it) by drilling out spotwelds or do I need to cut it out ?

Or should I just drop my car at a body shop and have them do it ?

Rob.