Before sending it to Lenovo, you could try with some USB or CD boot, just to see if the noise is still there with other operating system. That way you could be sure regarding if it's a hardware or software issue.
That's exactly what I did with Ubuntu. ;-) It's hardware, I'm afraid, though the noise goes off after around one hour of usage (but will return if I unplug and replug the audio jack).
I quite like the s430 as well. The two main quibbles I have with it are the unremovable battery (specially as it doesn't last long), and that I wish it had more USB ports, but few ports seems to be the trend nowadays.
Regarding Windows, I just did a fresh install. I have the same configuration as you do, except I added 4GB of RAM and a secondary HDD. Windows 8 is really fast in this machine.
I'm planning to add another RAM module as well, it's cheaper than having the factory upgrade. I'm using an external, not so fast, HDD at the moment.
Did you buy your licence for € 15 with MS's discount program?
I don't care about bundled software (and I like to be as far away from Symantec software as possible too). I just reinstalled the ThinkVantage and Lenovo tools I use: Active Protection System, Hotkeys, card reader driver, Intel drivers... and that's it. Most of the S430 hardware is being detected by Windows automatically and works better (and faster) without any additional software. The only tool still having compatibilities issues is Power Manager. But since the settings, once applied, are operating system independent, I'm not worried about it: I just set up the battery threshold and that's it.
Great! ThinkVantage is what I really want. The other software, not much anyway, I haven't had the opportunity to try yet, so I wanted to keep it in case some of it turns out to be good.
Norton is the first thing to go away from my computers. I rather have viruses!
I'm not very familiar with SSD technology, I just sort of copied and pasted the specs from my order sheet. The verbatim words are "Unité micro SSD 16 Go, Serial ATA3". I understand it's configured for caching. I'll need to run some heavily iterative search algorithms, so I was planning to try to use it for that, but now I'm reading these units have a short burnout cycle, so I'm not so sure.