xr4x4 front shafts are 8mm longer than cossie shafts as such you should have the circlip groove on the shaft that locates the cv machined 8mm further in effectively reducing the length....they should be installed diff end first then the hub end....they will fit and may not have any detrimental effect but the longer shaft alters the plunge depth of the cv and can lead to premature failure of the cv joint...

Regards

Ian