not that what i'll say is worth much here , but the possibility of adjustable cam pulleys slipping is a concern.....what you get is gucci looking pulleys - usually fully exposed to harmfull debri that can get caught in them an throw your valves off enough to whack your pistons - happened to me , but i lucked out on the interference. if you can't see them they arent of much consequence....cams are a better purchase - they can change timing AND duration. the adjustment range of the pulleys has to be experimented with to see much difference.
there i said it.