Had the DP raisers fitted to my 998bp & did not like them at all , sold them on this site , i found the best thing to do is to rotate the clutch/brake levers round which means your wrist's are not bent when operating them
This makes a huge difference ,so much now that my backside is usually the first to give in
Doing this will mean you have to either remove/file down the pins thaT locate the clip ons in position ,but as long as you mark the std position it easy to put back to std
Hope this helps