parts/angles for building exhaust system?

[rtha6551]

wanting to build up either a 2.5 or 3 inch bore exhaust from the decat pipe sleeve backwards? from mild steel

what angles of pre mandrel bent pipe do i need to get to mimic the original, and what lengths of straight pipe?

also the cost of buying the parts and having them fitted by an exhaust place versus having the same place make me one up from their own parts

any advice is appreciated