It's been a while I feel the urge to upgrade my polo's head unit. I was considering the RCD 510 but after learning the pain that I will have to go through during installation plus the effort to install USB/AUX petrifies me.
Hence the RCD 320 looks like a reasonable option. If anybody is interested in selling one, do let me know. I am also considering the RCD 510 if the deal is sweet.