NEVER had this type question in 44 years. BUT, I DO modify some of my equipment under warranty. IF I would ever have a problem, I would remove that added part before taking it in for warranty service. Never had a problem under warranty for those times I added a part. I had a start capacitor fail on my Home AC system. I replaced it, to get cooling until the Company could come out and diagnose and fix. Before they showed up, I removed MY new capacitor and installed the defective one. Did NOT tell them what I did, just like you, did not want to get in a problem with ME touching the system under warranty. Doug
Here's the problem with soft start caps; If the original cap dies while the AC is running, rather than stopping like it normally would the AC will continue to run on the new cap and destroy the compressor.