I've got mideival front and rear mounts with awr side inserts, had the insert in at first and there was hardly no additional vibration, but after I got the front and rear solid mounts in... I said goodbye to wheel hop forever
i always say you get what you pay for, a 4-1 header will give mostly high end power gain as were a 4-2-1 header will add more power into the mid-range of the power band as well as the top-end