Yes there is an improvement or more accurately a difference with aftermarket cables vs stock on the Silver. Whether or not that difference is perceived as significant or an improvement is highly subjective and will vary with the listener. The stock cable performs very well though.
As stated in my prevous post I got very good results with the Plussound cable, but even better results recently (more natural midrange and treble) with the Penon Audio GD849. I thought the GD849 would be too thick to work comfortably with the RE2000, but was pleasantly surprised to find out that was not the case.
The impact of balanced versus single ended will likely depend on the DAP. On the QP2R there is an improvement.
The previous post by
@Dobrescu George and
@twister6 on his website both do a great job comparing the Silver to the original Gold. Summary: Silver is more comfortable, better balanced and closer to a neutral signature. A much better buy and a steal at the special price IMO.