I ave the MSD cap/rotor and they are a good piece, but for 200 shipped (i think the price is close to that), you can get a whole newopti from Bigbadwolf.
if UI had known that the MSD cap/rotor would be such a PITA I would have gone that route myself.
Beware the tiny bastard screws they give you to put the rotor on with and take your time putting it on. I ended up having to drill the f'ing screw head off and using vicegrips to extract the rest, then used the stock bolts off the old rotor.
I have used three with no problems except removing one (bad optical sensor). I had the same problems with the tiny screws on the rotor and had to drill one out. If you get a MSD cap and rotor reuse all the factory screws.