Please note that Dolby Surround may modify your sound, giving you sounds that may sound good, but won't be accurate in a stereo sense. The "gradfun video filter" also is just a filter, that may filter how all video looks to you and therefore may deliver inaccurate results.
I don't know what the "SincR" upscaling does... everyone mentions to use it.
Do remember to think about this, especially if you are someone who wants to listen to their own music or view their own videos. Filtering out bad things means you won't notice them. I personally prefer watching/listening in the closest to original way possible, regardless of whether I made it or someone else, so I don't apply filters, stereo wideners, EQs, Compressors on my audio and filters, un-distorters, etc on my videos when I use apps like VLC. Anything that "improves the quality" of media on a media player is a no-no for me- I want something that gives me the closest to original.
The main reason it sounds different is because the resampler resamples your sound, and the Dolby Surround forces the sound through its algorithm giving it a sense of surround sound. The former is good, but personally I feel the latter can make you think something sounds better than it actually does.
Remember whenever someone suggests something that makes your audio/video seem better in a media player: do you want to view it closest to the original, or with a bunch of misleading filters on?