Oh okay I guess I didn't make myself very clear earlier on Flashp.
Let me clarify the situation for you.
I have a complete turbo back Miltek system currently fitted on the car. Thats the down pipe, high flow sports cat, resonated centre section, rear silencer and jet trims. With all other hardware the car is stage 2+ tuned by Rtech and on their road achieved pub talk headline figures of 276bhp and 327ftlbs for what it is worth.
I was just asking about whether there would be any gains to be had at this level of tune by swapping out the Miltek rear silencer section, which snakes around the back of the car for a more direct rear section like the BCS which just swerves around the rear arm and out. In stage 2+ tune the little K03 turbo is pretty much maxed out and apart from perhaps fitting a stronger actuator the only way of getting more performance as far as I can see would be to look at improving the flow in and out of the engine.
Mappers will no doubt notice that they are able to squeeze more out from certain hardware designs, between CAI's for example. Some will allow for more gains than others. As exhaust design requires the careful balancing of flow capacity with velocity I am interested to learn if at this level of tune a more direct rear section would preform better and if so can I mix and match rear sections between the two manufactures?
There must have been a reason for both companies choosing to settle on their end design. Has any body A,B tested any zorts?
Thanks for clarifying this, I'm with you now!
I think you already have an excellent system that will be doing all an exhaust can for your car in it's current tune.
I also think different manufacturers have responded to different market demands, and that is after all good business sense. Some have focussed on the customer requirement for a different exhaust note and others less so by going for an OE replacement that might be more discreet. I'm not qualified to say so, but I imagine that one may not perform any differently from the other in terms of engine benefits and technical function. I think that most, if not all of the premium brands have achieved correct technical function and good build quality but have added different appealing features. Aesthetically I think they can vary hugely.
In short, I think you'll add nothing to the car by changing from a technical perspective. If however you wanted a different exhaust note then going by reviews I would say a BCS system would give it to you. If by adding a BCS system to Milltek downpipe there's a change in pipe diameter it may be considered beneficial to maintain the same diameter throughout.
I bought my Milltek new and so I have excellent warranty support as the original purchaser, maybe you have the same benefit? I also know that my system will get through the tightest of static noise tests at a circuit. This may or may not be an issue for you. I've no idea where a BCS system is on this front.