I've heard apex's have poor accuracy, but I may be wrong, I don't know as I've never used one.
The Freak will be your better option as you can then bore match your paint and so it'll be more efficient and slightly more accurate.
if you are going to use the short shroud with the sp8 then there is another alternative.
the freak kit will give you an improvement on accuracy and consistancy by providing bore matching for your paint.
if you really want to use an apex then SP are now producing a freak front that comes with the end milled to accept the tip form an apex barrel. you will need the longer of the two lengths available to fit in the short sp8 shroud. you will also need to buy your own apex - however as you only want the tip any thread will do - try ebay.