They work excellent for a rering as they remove little to no material plus give an excellent plateau'd finish. The out of round/taper you had before is the out of round taper you'll have now. Follow their instructions for drill speed/rate etc. They (BRM) have a list of OEM/aftermarket satisfied users a mile long who swear by it. Best use is to bore and ck-10 rigid hone to size then plateau it w the dingleberry. They (BRM) want you to bore to size then dingleberry w no rigid hone, I disagree there, the ball hone only hits/creates the surface plateau not deeper like a rigid hone does & prob is then you can easily wear past the plateau's and be into rough territory but you need the ball hone for the final plateau that the rigid hone does not deliver