For a naturally asperated engine, the VEC2 might be over-kill. It's a good system, but it's $1000. The VEC1 doesn't give seperate control of fuel and timing, so if you really like to "tweak" your settings you'll want more.
Split second has a fuel/timing map system I'd like to check out. It's not viper specific, so you'll have to know what you're doing when you install it. But it looks like it's about $500.