Hey guys. I am new to the Z28 scene. I have a 94Z. Is an SLP resonator a replacement for the catalytic convertor?? I noticed the resonator only has 2 holes....doesn't there need to be 3 holes?? I am trying to learn everything. If so, what kind of sound and HP gain can I expect with this?? My car is stock except for SLP shortshift and 3.42 gears. Thanks.