Actually Id recommend a Duo Chip or Apple Chip for a v4. Apple's only cost $20 w/free shipping and Duo's cost $21 w/free shipping.
Only real differene between the 2 is that the Duo has 17 wires to connect and the Apple has 22 (I think).
This is based on NTSC systems only.
go here for more details on everything
www.modchips.cc
Tyler!