Yes, the bottom HDD cage from the Define R4 will fit next to the other HDD cages in these models:
Arc Midi R2
Arc XL
Define R4
Define XL R2
The cage will fit on the 140mm fan slot mounting holes and there will be less space for mounting a power supply.
The distance from the back of the case and to the additional HDD cage will be:
210mm in:
Arc XL
Define XL R2
180mm in:
Define R4
Arc Midi R2
We recommend mounting power supplies slightly shorter than the measured distance in order to fit the cables on the power supply.
