Hi there
Great question.
The exhaust system should be able to fulfil 4 basic principals...
1) Increase the performance and the performance potential of the car
2) Improve the sound quality of the car
3) Be an up grade optically with regard to the tail pipe style
4) Should be supplied with a lifetime guarantee (If stainless) that can be backed up
There are many brands that claim to fulfil these promises, but ultimately the 'proof of the pudding.....' as they say.
Performance can be measured, but the sound and look have to be discerned and are therefore far more subjective qualities. Fortunately the forum members are able to add credibility or complaint to a particular brand by providing direct feedback and consumer reviews after purchasing and fitting.
For me personally it boils down to the passion that has been expended in the design and development of a product. Has it been extensively tested, does it leave you with a feeling of "Yes that was the right choice", or "it's okay but I just wished....."
Very often a brand can start out with a clear vision as to it's market, its product and customer requirements, but somewhere in the mix and as time goes by and complacency sets in, passion can be replaced by formula and economic need.
Of course the final consideration has to be the cost. Again it's easy to be drawn into the notion that if something 'costs the most' it must 'be the best'.
Here it's once again a case of do your research thoroughly first, and satisfy yourself that you made the right choice.
In summary the world of performance stainless steel exhaust systems should always be (IMHO) considered as a niche product type which contains within it's DNA something of the character of the man who designed and manufactured it. Along with an absolute desire to strive for excellence, for in the final analysis we are all measurable by our efforts in what we do and the mark we leave on the people we come across as we journey through life.
You could of course just stick with the standard VW system and save the money. But then.......
Cheers
Nige
BCS Automotive