I have had enough of having to change bottom arms on my 307 so i have decided to buy the power flex bushes and fit them to my current arms and hope they last a bit longer. my question is though the bottom arms i have on there at the moment are after market ones from ECP . are they going to have the same diameter bushes in as genuine? as even just a mm difference is going to cause problems. also any way to tell what diameter my anti roll bar is or do i need to just measure it.