I have been buying from Stillen 4 years, I had a G35 coupe and have a G37S coupe now. Everything I bought for my G35 coupe was perfect; Z tube intake, grounding kit, headers, exhaust... it goes on, but nothing for my G37S coupe was manufactured with ANY quality. I paid a lot of money for my Stillen Grille... my Infiniti dealership had to modify the front inside fascia of my car so it would bolt on, it did not match up, but I allowed them to do that and it worked and it looks good on the outside, so I was okay with that because I had a great history with them, but my next purchase was cross-drilled rotors and pads. I purchased the set for around $600, I went through two sets and they were both warped. Both times Infiniti went through Stillen's rigorous break-in steps, but both times, the runout measurements were out of specs, they tried to get me to try a third set or drive the second set until they were worn in, but after buying them and paying $2,000 in labor to try and make them suitable, I asked for a refund if I kept the 2nd set and they didn't wear in, but they said they would not refund afterwards.
I then said, no thanks, I want a refund now for your defective parts, they gave me a hassle, but thankfully, Infiniti was behind me which gave me a little leverage. They agreed to give me a FULL refund, so I sent the pads and rotors to them, they did not refund the pads, kept them and gave me a partial refund. I'm not sure what's happened to Stillen or their quality, but by their lack of caring for their customers now is very sad. Be aware!