What they're doing isn't a 5 minute job. The resistors in question are in tight spots and the whole amp has to be disassembled.
There are 2 electrolytic caps in the signal path(per channel) that I'm thinking about bypassing with Jensen copper foil caps, either copper or paper casing. The caps W4S used are good for electrolytics(Nichicon Muse), but still aren't as good as a high quality film cap. If they weren't such a large value(10uf), I'd just replace them with a good film altogether. Not that I feel as the amp is lacking at all, but there's always something better.