If you have a custom cam profile (or are racing) and want to fine tune then it's a valuable item. For stock cams, there is no use for variable pulleys because the factory already did the tuning work for you.
If you switch cams to another factory option (107, or 104) you will want to use the 104 pulleys available at JAE or the other usual suspects..
Read more about the complexity of engine and cam timing at http://www.elgincams.com
Lucky for us Lotus did another 20 years of engine development after the JH and all we have to do is bolt-on the parts!
Just throw in some 107 cams with 104 pulleys and enjoy the car. You can't get the maximum benefit from 104 cams with the stock 8.5:1 bottom end.
If you have more money then go to the 2.2 crank and 11:1 pistons with 104 cams and 200 HP.