Hi VipeRx,
The Dynojet brand is the "standard" in the industry and results are typically consistent between them. The Mustang and Clayton load style show different results (lower), but are equally beneficial, if not more so, for tuning. We have a Clayton dyno here that we use for load tuning (can simulate highway cruising to uphill pulls at full throttle). But, when we need to obtain / show "standard" figures, we go to a shop with a Dynojet.
Regarding tuning of the engine, contact me at the shop or by e-mail if you need the latest Smart Cards for the VEC2 (Rev 6 cards). We will have the software for tuning yourself soon (you've heard that before, I know, what a long project). In the mean time, we'll be glad to make changes, if necessary, based on your dyno results (get an air / fuel reading, write which program card you were using and fax it to us).
Regards,
Sean