a Longlife exhaust depot will build a bespoke system for you, including being able to control the sound it maes (combination of pipe size, number, size and type of silencers)
https://www.longlife.co.uk/dealerClosest to you is Longlife Leeds
Unit 6 Lakeside Industrial Estate
Lakeside
LS12 4QP
Telephone 01132 089 830
PS - no vested interest, but Motormech used to operate the Birmingham Longlife franchise - I know the materials are very good (stay away from Powerflow if you can - same company, but the materials are not as good)
I still have a 3" Longlife system on my car - it has done over 150,000 miles and is still perfect