Is it possible to downgrade US client 4.3 back to 4.2? /cry
Keep your 4.3 unmodified client and download a new one through the Stream Installer. I suggest using the one from Great Britain. The english isn't different at all, except for 'color' being changed to 'colour' . Strangely, the download is much faster than the US client. Stixx and I can vouch for the enGB client.