if your staying Obd0 you will never fully benefit from the vtec head so i'd say go with the A6 head built. By staying obd0 and using vtec there really is'nt a realy deal way to use vtec, i mean you can get an expensive vafc controller but it still is'nt the same, you just can't tune it the way you can if you go obd1. If your converting to obd1 though the Z6 will always win, its just a better design all around.