Ok, lets try to continue the build story.
As I've been runinng a Viper business for many years (not now though) we had many choices picking headers. We dynoed with 4 different sets, didn't see much difference.
Ended up with a set of American Racing Headers. Nice work, perfect fit. Probably not the best performing set, but good enough for us.
IMG_3911 by
j.phersson, on Flickr
The exhaust routing and frame on a Viper makes it impossible to exit headers under the car, this is the only way to do it.
2012-04-21 17.56.57 by
j.phersson, on Flickr