The big misconception that many people have with a warranty issue is that any modification or use of a non-OEM product (like oil) will void the warranty in its entirety. This is simply not true.
If, for example, you decided to use another brand of oil, filter, spark plug, tire, etc., the manufacturer MUST prove that a warranty covered failure was due in full, or at least in part, to the non-OEM item. If the non-OEM item meets or exceeds the OEM specs then the manufacturer has no basis for any refusal of warranty coverage.
But let's say you made a big mistake and used an inappropriate oil and you suffered engine damage because of it. This action, on your part, would void ONLY the warranty coverage for the affected part. All other warranty coverage NOT affected by using the wrong oil would still be in full effect.
In regard to my custom sway bars, I cannot honestly give an iron clad statement because no one has had any issues related to my sway bar to test this. But my feeling is that having the bar isn't going to endanger your warranty. First, I can't think of any warranty item that would be affected, one way or the other, by my sway bar being installed. Nor can I think of any non-warranty component that would be affected.
I can tell you that many dealerships are installing my bars, and to my knowledge have never made any mention to the owner of even a possible warranty issue.