well I did have a vafc but ended up selling it. I had bought it used but never installed it because of the complexity of tuning. I dont have the knowledge to be able to fiddle around with the air/fuel, ect. I guess I would have to stick it on a dyno to get the best power throughout the rpm band.

That really sucks you can only use the vpac at 4000. But still its better than 5800-6000.