VANOS give drivability through out the full rev range from tick over to the red line
With the VANOS removed you loose this but you can gain top end power by other mods but these then only work at the top end of the revs ie.7,000 to 9,000rpm so you need to drive it like a race car full throttle or on the brakes.
If you go too far you need to have around 4,00 rpm just to get off the line and your rear tyres become your clutch fun for a short time but not a road car.