Having fitted this yesterday, I've noticed the car seems much more free and definitely more spirited when you floor it. I sit possible that the combination of the Apexi and manifold could have increased the bhp? It definitely feels much quicker 0-60 than it did before.
Also, it's a darn site louder suddenly! That manifold/apexi combo sounds absolutely stunning!
Well the gas flow must have improved by getting rid of the precats and their chamber, so its possible; though the Apexi is generally thought not to add to bhp, only to smiles per gallon! The absence of the precats will probably add to the aural experience. Bet it sounds great.
you might have made 3-5bhp if your lucky, but as you say throttle response is the most noticeable difference
Quote from: "Slurpy J"It definitely feels much quicker 0-60 than it did before.
Also, it's a darn site louder suddenly
Loud often gives the impression of faster.