Angle, dimensions and exhaust

Hello dear Leuts, I would like to build my own exhaust for my Volvo, because I am not willing to spend a lot of money on a tuning exhaust. If someone had a sketch of Volvo directly or there is something where all dimensions and angles are in a construction plan for the original exhaust, I have not found anything yet. Would be very nice of you, if someone has a clue about and could help me further MfG