On all three my golf GTI's in the past 4 years.
I have used, Remus car back, Miltek, APR RSC and currently BCS power. Valve catless.
Overall fit and quality hands down to the BCS.
Miltek broke at joints as well as burnt out the glass fibre in the mufflers.
APR was loud outside but never even remotely intrusive in the cabin.
The remus rusted out.
This time I tried the BCS system. I can't be more happy if I tried. Been on my car for around 3 months.
Also did a 1900km round trip last weekend. Sounded great when required.
If the APR system was not so expensive I might get one again. But quality, sound, fitment and price.
BCS all the way!!!!