Just open up another option..
What would it cost roughly to fully decat the standard GTI K03 or ED30 K04 exhaust? meaning the Precat and the main cat?
Im sure this would open up more power / power delivery performance and also more sound if thats all the OP is wanting? Rather than paying out £400+ or possibly £1000+ if going for a new full TB system..
So what I'm saying here is either fully decat standard system or..
Just change the standard downpipe for a 3" aftermarket one and take the main cat out or install a sports cat such as a 100/200 cel cat rather than the standard 800 cel cat?.. Then would you not get the same outcome as you would paying £1000+ for a new full BCS TB exhaust?.. Yeah you don't have BCS stamped on some tips or its not all shiny and have some trickery with valves etc but if your looking to stay on a tight budget and you want some more power / power delivery and more sound.. this could be ideal?..