Well im not saying anything bad about either brand, however i heard this from someone, so dont hold it to me, its just what i heard. I heard that GIAC's technology was orginally ripped off from APR technology, and then they tweaked it. Nothing against GIAC, i have it in my car and its not giving me much trouble (just some surging issues that started with the X+), but when i had their socket type chip it was the smoothest and very powerful chip that I have ever felt