the spec2 valve will open at around 6.5 
..the vtec will open at around 7.5 
..........when spec2 valve open and u never drag the bike
,,,,and change gear when the valve just open,its not gd for the
valve 
,open and close the valve will spoilt it soon 
,,,,too early
open valve not really that gd ,it
means if never drag the bike after the valve open,,,after few
months the valve will need servicing.....vtec open valve slightly
later which u can change gear before the valve open 
,,,,,so i think vtec is much more better,,,so far i
seldom see that vtec need to service valve,,,,,,,but spec2 i have
seen a few already sent for servicing for valve.......correct me if
i am wrong... 
i am not a mechanic nor a S4 lover....just hear from my friends
which have use both bikes.
