That pioneer looks pretty good. I know the becker mexico has a decent (my opinion) display and stats. Even the display colours match the golfs.
I recently used the following for speakers an amp. They was
www.caraudioplus.co.uk and
www.caraudiodirect.com the later helped with me some tech info and help installing so top stuff from them. Email support great too. Dont work for them just had a good recent experience with them as can be seen in a thread somewhere in the audio forum.
I was told to get some good front speakers amp them then amp a sub. And the sound is fantastic I have little hearing left but with so much stuff in braile who needs ears ÂÂÂ

but its all down to taste of music.
Also something I didnt know is you look at the rms rating as oposed to the watt rating of a speaker. I bought the alpine splp17's lovely speakers just for the front though.
But those websites have a big selection of stuff worth a look but maybe able to find stuff cheaper elsewhere.
Happy Hunting.