No. DO NOT mess around with the actuation of the VICS!!!
I can assure you that the japanese engineers who built that engine know a hell of a lot more about it than we little ******** do. Leave it alone.
Reason why the even put VICS into the engine is because at low rpms, you want high velocity gas to be diverted from the plenum through the intake runners and into the cylinder. When the VICS butterfly valves open, the air is not only through the runners like before, but also through the bottom of the plenum itself, feeding the engine for the air it desparately needs at high rpms. If you open these valves earlier, then you are losing your torque because you are bypassing the runners when the velocity of the intake gas isn´t up yet.
HOWEVER... if you do mods to your intake like I did, you will notice a difference in when the VICS kicks in. Stock, my VICS kicked in at about 4900-5100rpm. Then when I threw in the K&N filter and the RX-7 VAF and did a couple a/f mods (like you´ll see in the post "cold air idle valve") I managed to drop the actuation of the VICS at WOT from around 5Krpm to 3.9K rpm. Needless to say, my GT pulls more in the higher band, no doubt.
VICS works on vacuum pressure (which is a misnomer, but oh well) so yes, you can modify it with slight difficulty, but I suggest leaving it alone because you´re messing with the physics that the engine was originally designed with.