Heads: what works best?

[Supercharged Vipermad]

Seem to me that I hear people have great performance gains with head work/performance aftermarket heads...

Questions:
What companies make aftermarket performance heads for the Viper?

What flow rates/porting seems to be the best combo for a stock bottom end & stock cam 98 GTS? Other mods include headers, exhaust, filter, tubes...

Is it necessary to upgrade or reprogram the PCM?

Anyone have a dyno numbers for heads only?

Where cna I find the most competitive prices?
Thanks!