I had a back box made in a franchise in croydon and tbh I wasn't happy with the end result , they couldn't be bothered to unbolt a flange so cut it off and sleeved it to centre pipe instead and box was really loud with the car being an auto at the time so they agreed to put on another box but said I had to re use the chosen tail pipe tip and they would charge me extra too , the tip itself was poor quality and not the same shiny material as the box so overall poor service and quality for me and even when I desperately needed a centre Pipe I refused to go back so instead I went to powerflow but they too can be hit and miss as I had a front pipe made in one branch and service and quality was great but the branch lost there certificate with powerflow and they were waiting to hear about it being renewed but they didn't so went to another branch recently and they had to alter the pipe for another manifold and they really bodged it and ruined the great work of the original powerflow branch , my advice would be make sure you research the branch well wherever you want to go