What ever you do, do NOT attempt to bend the exhaust pipe while it is still attached to the engine....You will only break the mounting studs or worse pull the studs out and mess up the threads in the cylinder head (it can be fixed but is a pain).
I have done minor bending by removing the pipe and clamping the exhaust in a large vice and man handling it.....some here will recommend using heat to help soften the metal.....I have not found it to be necessary though.
Hope this helps,
Andrew