I've done the pre-vtec (my fi-y) which was easy-the vtec is harder because of the extra valves which need more thought/experience.
I think it all comes down to how 'spannered up' you are?
Obviously, there are different schools of thought on if they need doing at all,or if you can just' do the non vtec clearances...
I'm old school & sleep better knowing they're done

(all my humble opinion of course)
p.s. my fi-y ones were all in tolerance!

hth-yann