Ive had the Sp. cat fitted for a day now, with a stealth system, from K-TEC. Havent had chance to give it some as the roads have been shocking. The sport cat is without doubt allowing the engine to breathe more easily. The revs increase quicker and fall faster than before, when driving or in neutral.
Its been hard to say if I could feel a power increase, I mean, what does a 6-7bhp increase feel like when youve already got a 165+bhp car? Having said that, there feels like there is more tourqe at lower revs when driving slowly.
All in all, Im dead chuffed with both products. The service offered could not be improved! The warranty and after sales on these products is also second to none, with a return to base/replace type policy.
The products might seem a bit expensive, but when you get what Ive mentioned, its cheap. You buy cheap, you get crap!!
^^^^^^^This is only my opinion..
Oh yeah, the system is not aggresively loud but subtl and sporty.