Garage recommendations for the "2 pipe" exhaust mod on my M3

[jeffersWales]

Might be a bit of a long shot but does anyone know of a garage in South Wales (Newport/Cardif area) which have experience in doing the 2 pipe mod on an E92 M3 exhaust back box? I dont think its hard to do but would prefer to go to someone who's done it before.

Heres what im talking about (but this guy is up near Milton Keanes).. https://www.exhaustmods.co.uk/e92-m3-exhaust-mod

[Bhp1000]

No doubt Charlie at Prospeed Exhausts can do it