Sorry Jamie I don't know yet. Larry should be able to advise now they've completed the work on mine. I only found out the forks weren't compatible with M4's after I'd bought them. Seems strange Ohlins didn't allow for spacers as per the stock forks.
I knew before I bought them from an American blade site and decided to sell M4s I had and buy HPKs but they are pricey so keep coming back to the M4s if the machining isn't stupid price wise. Will give them a ring see what they say Big oversight by ohlins in this IMO
Thanks spoke to them all sounds quite straight forward to do so should be getting them done some time soon thanks for the info
I have a pair being milled as we speak, cost will depend on time but I will post back once done, seems the easy option as now any caliper will fit.