Every mark 2 Golf has speakers in the dash. Some as part of the orginal component set and some as the only speaker. In mine the centre has been cut out and the rest used as a mount to house the new tweeters.
I know what you mean about the rear speakers. I've done a ton of sound proofing in the boot and have tried it with front components and a rea sub and the same with rear speakers. Everytime I've found it sounds better and more equal with the extra rear speakers. With 13cm front components and the rear sub, to me it sounded as if just the trebl and bass were coming from the front and just the bass from the back. With the rear speakers it sounds like it's more around you and not separated!
I've had some top quality 13cm Boston acoustics front components for sale for a while now at £60 (less than half they cost me) and they sound a lot better than the usual Kenwood, Pioneer, Alpine speakers that everyone goes for because that's all they have heard of. They pick up a lot more detail too. Usually in hi-fi gear it's the makes that you haven't heard of that give the better sound. Ask any audio shop that knows thei stuff. Not heard anything bad about them yet. Some of the best makes of speakers are: Focal, Rainbow, Hertz, Boston acoustics and DLS.
Also got a new Phoenix Gold mono amp and a mint Kenwood 7031 CD headunit if anyones interested?!