i have had an apex N1 and now a greddy evo 2. depends on how loud you want it. the N! was loud on my si, basically no sneaking around for sure. i love the greddy too and most people like the sound of the greddy. either way they have both been good to me but like i said the N1 is loud as hell. check out a greddy to see what you think. the N1 has a silencer i think but im not sure if it makes a difference i never used it. i think the greddy also came with one but i never used it. the greddy has a lower eshaust note andthe N! is higher, kind of like a racecar. peace, pm me if you need video/qudio of my greddy setup.