making custom exhaust

[rd070707]

Right I've had enough of my cat sitting to low and catching on speedbumps etc so I want to make a 2.5 inch system from the turbo back with a dummy back box .

few questions:

- what diameter is the downpipe currently? Should I weld the 2.5 inch pipe from the very top of the downpipe where it meets turbo or can I just do it after the bend?

- for the bend in the mid section would it work to just buy two 45 degree bends and weld them in?
Or would the likes of a 307 have a 2.5 inch exhaust with suitable mid section bends?

cheers