As far as I'm aware, there are no direct swap speakers other than the Dynaudio sound pack upgrade option. But for the hassle of it all I'd opt for some decent after market speakers from JL Audio or similar good brands. You can get adaptor rings which come with the wiring connections so you don't have to hack apart your car's original wiring to fit them.
Alternatively, get a Kenwood DNX525DAB, it's a proper after market unit but it's also VW approved to it fits like an OEM unit, supports all the OE features but should have better sound due to the much better amplifier technology on board. I ran a Kenwood DNX520VBT in my mk5 GTI and it was far better than an OEM stereo, plus if you later combine it with better speakers it supports them much better. Plus you can run external amplifiers off of it which gives you even better sound (it was what I did for my rear speakers in the GTI, the difference over OE setup was amazing).