Uh.. you can't really softmod an A2ZS to an A4, at least not in the sense that you could softmod a Radeon 9500 to a 9700. You might be able to get the same feature set (most of that stuff is done in software anyway), but the A4 actually uses different hardware (better DACs, too), so you can't really make one into the other without a soldering iron and a lot of patience.
DEC Pentium X2 5200+ w/ HyperCache (Ezra core)
Asus M7NCD-MAX3 (OPTi Vendetta 82C760)
6x Generic 32MB PC2700 RDRAM (50ns SIMMs)
2x nVidia Millennium X1800 Duo (SLI mode)
12x (daisy-chained) Quantum Medalist 180GXP (w/ separate SCSI-1 adapter)
"Oh, you started a Rube Goldberg machine. A Rube Goldberg machine... called JUSTICE." <a href='http://www.boomspeed.com/old_camper/amdforumsircchat.ht