Updating to 4.3 gets you absolutely nothing. The defacto preferred sysmenu is 4.1.
The latest softmod guide is in my sig, and all ioses are included with it. IOSes (as opposed to cIOSes) are only used for original games when played from the original disc. If you're usb loading (you should be!) you don't really even need to mess with them. Newbies thread in my sig has more info.
One note, we have not yet adopted dx2v8 in our guide; would be v7.