are ET making you a custom exhaust or supplying the off the shelf marco gold exhaust?
from what it appears the marco gold exhaust and the KPM exhaust are exactly the same. It's probably become cheaper for the both of them to source from overseas from the exact same supplier. They just would have collaborated on the design and exported the production
if you compare the pics of the exhaust
here to a KPM exhaust they're completely identical in looks and price.
so saying one is better than the other means nothing, unless ET are completely custom fabbing an exhaust for you